Uninstalling a package removes all of ROS

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I am trying to remove the Boost package from my Ubuntu 18.04 system. On giving this command

sudo apt-get remove --purge libboost-dev

Apt says that the following packages will be removed, and all of ROS is printed here.

Here is a sample of the same.

The following packages will be REMOVED:
  libboost-all-dev* libboost-dev* libgazebo9-dev* libgdal-dev* libkml-dev* libogre-1.9-dev* libpcl-dev* libvtk6-dev* libvtk6-qt-dev* libyaml-cpp-dev* ros-melodic-ackermann-steering-controller*
  ros-melodic-actionlib* ros-melodic-actionlib-msgs* ros-melodic-actionlib-tutorials* ros-melodic-bond* ros-melodic-bond-core* ros-melodic-bondcpp* ros-melodic-bondpy* ros-melodic-camera-calibration*
  ros-melodic-camera-calibration-parsers* ros-melodic-camera-info-manager* ros-melodic-class-loader* ros-melodic-combined-robot-hw* ros-melodic-common-msgs* ros-melodic-common-tutorials*
  ros-melodic-compressed-depth-image-transport* ros-melodic-compressed-image-transport* ros-melodic-control-msgs* ros-melodic-control-toolbox* ros-melodic-controller-interface* ros-melodic-controller-manager*
  ros-melodic-controller-manager-msgs* ros-melodic-cpp-common* ros-melodic-cv-bridge* ros-melodic-ddynamic-reconfigure* ros-melodic-depth-image-proc* ros-melodic-desktop* ros-melodic-desktop-full*
  ros-melodic-diagnostic-aggregator* ros-melodic-diagnostic-analysis* ros-melodic-diagnostic-common-diagnostics* ros-melodic-diagnostic-msgs* ros-melodic-diagnostic-updater* ros-melodic-diagnostics*
  ros-melodic-diff-drive-controller* ros-melodic-dynamic-reconfigure* ros-melodic-effort-controllers* ros-melodic-eigen-conversions* ros-melodic-eigenpy* ros-melodic-executive-smach* ros-melodic-filters*
  ros-melodic-force-torque-sensor-controller* ros-melodic-forward-command-controller* ros-melodic-franka-description* ros-melodic-gazebo-dev* ros-melodic-gazebo-msgs* ros-melodic-gazebo-plugins*
  ros-melodic-gazebo-ros* ros-melodic-gazebo-ros-control* ros-melodic-gazebo-ros-pkgs* ros-melodic-geometric-shapes* ros-melodic-geometry* ros-melodic-geometry-msgs* ros-melodic-geometry-tutorials*
  ros-melodic-graph-msgs* ros-melodic-gripper-action-controller* ros-melodic-hardware-interface* ros-melodic-image-common* ros-melodic-image-geometry* ros-melodic-image-pipeline* ros-melodic-image-proc*
  ros-melodic-image-publisher* ros-melodic-image-rotate* ros-melodic-image-transport* ros-melodic-image-transport-plugins* ros-melodic-image-view* ros-melodic-imu-sensor-controller*
  ros-melodic-interactive-marker-tutorials* ros-melodic-interactive-markers* ros-melodic-joint-limits-interface* ros-melodic-joint-state-controller* ros-melodic-joint-state-publisher*
  ros-melodic-joint-state-publisher-gui* ros-melodic-joint-trajectory-controller* ros-melodic-joy* ros-melodic-joy-teleop* ros-melodic-kdl-conversions* ros-melodic-kdl-parser* ros-melodic-kdl-parser-py*
  ros-melodic-laser-assembler* ros-melodic-laser-filters* ros-melodic-laser-geometry* ros-melodic-laser-pipeline* ros-melodic-librviz-tutorial* ros-melodic-map-msgs* ros-melodic-message-filters*
  ros-melodic-message-runtime* ros-melodic-mk* ros-melodic-moveit-core* ros-melodic-moveit-msgs* ros-melodic-moveit-resources* ros-melodic-moveit-ros-perception* ros-melodic-moveit-ros-planning*
  ros-melodic-moveit-visual-tools* ros-melodic-nav-msgs* ros-melodic-nodelet* ros-melodic-nodelet-core* ros-melodic-nodelet-topic-tools* ros-melodic-nodelet-tutorial-math* ros-melodic-object-recognition-msgs*
  ros-melodic-octomap-msgs* ros-melodic-ompl* ros-melodic-pcl-conversions* ros-melodic-pcl-msgs* ros-melodic-pcl-ros* ros-melodic-perception* ros-melodic-perception-pcl* ros-melodic-pluginlib*
  ros-melodic-pluginlib-tutorials* ros-melodic-polled-camera* ros-melodic-position-controllers* ros-melodic-qt-gui-cpp* ros-melodic-random-numbers* ros-melodic-realtime-tools* ros-melodic-resource-retriever*
  ros-melodic-robot* ros-melodic-robot-state-publisher* ros-melodic-ros* ros-melodic-ros-base* ros-melodic-ros-comm* ros-melodic-ros-control* ros-melodic-ros-controllers* ros-melodic-ros-core*
  ros-melodic-ros-pytest* ros-melodic-ros-tutorials* ros-melodic-rosbag* ros-melodic-rosbag-storage* ros-melodic-rosbash* ros-melodic-rosbuild* ros-melodic-rosconsole* ros-melodic-rosconsole-bridge*
  ros-melodic-roscpp* ros-melodic-roscpp-core* ros-melodic-roscpp-serialization* ros-melodic-roscpp-traits* ros-melodic-roscpp-tutorials* ros-melodic-roscreate* ros-melodic-rosgraph-msgs*
  ros-melodic-roslaunch* ros-melodic-roslib* ros-melodic-roslisp* ros-melodic-rosmsg* ros-melodic-rosnode* ros-melodic-rosout* ros-melodic-rospack* ros-melodic-rosparam-shortcuts* ros-melodic-rospy*
  ros-melodic-rospy-tutorials* ros-melodic-rosservice* ros-melodic-rostest* ros-melodic-rostime* ros-melodic-rostopic* ros-melodic-rosunit* ros-melodic-roswtf* ros-melodic-rqt-action* ros-melodic-rqt-bag*
  ros-melodic-rqt-bag-plugins* ros-melodic-rqt-common-plugins* ros-melodic-rqt-console* ros-melodic-rqt-dep* ros-melodic-rqt-graph* ros-melodic-rqt-gui-cpp* ros-melodic-rqt-gui-py* ros-melodic-rqt-image-view*
  ros-melodic-rqt-launch* ros-melodic-rqt-logger-level* ros-melodic-rqt-moveit* ros-melodic-rqt-msg* ros-melodic-rqt-nav-view* ros-melodic-rqt-plot* ros-melodic-rqt-pose-view* ros-melodic-rqt-publisher*
  ros-melodic-rqt-py-common* ros-melodic-rqt-py-console* ros-melodic-rqt-reconfigure* ros-melodic-rqt-robot-dashboard* ros-melodic-rqt-robot-monitor* ros-melodic-rqt-robot-plugins*
  ros-melodic-rqt-robot-steering* ros-melodic-rqt-runtime-monitor* ros-melodic-rqt-rviz* ros-melodic-rqt-service-caller* ros-melodic-rqt-shell* ros-melodic-rqt-srv* ros-melodic-rqt-tf-tree*
  ros-melodic-rqt-top* ros-melodic-rqt-topic* ros-melodic-rqt-web* ros-melodic-rviz* ros-melodic-rviz-plugin-tutorials* ros-melodic-rviz-python-tutorial* ros-melodic-rviz-visual-tools* ros-melodic-self-test*
  ros-melodic-sensor-msgs* ros-melodic-shape-msgs* ros-melodic-simulators* ros-melodic-smach-msgs* ros-melodic-smach-ros* ros-melodic-spacenav-node* ros-melodic-srdfdom* ros-melodic-stage-ros*
  ros-melodic-std-msgs* ros-melodic-std-srvs* ros-melodic-stereo-image-proc* ros-melodic-stereo-msgs* ros-melodic-teleop-tools-msgs* ros-melodic-tf* ros-melodic-tf-conversions* ros-melodic-tf2*
  ros-melodic-tf2-eigen* ros-melodic-tf2-geometry-msgs* ros-melodic-tf2-kdl* ros-melodic-tf2-msgs* ros-melodic-tf2-py* ros-melodic-tf2-ros* ros-melodic-tf2-tools* ros-melodic-theora-image-transport*
  ros-melodic-topic-tools* ros-melodic-trajectory-msgs* ros-melodic-transmission-interface* ros-melodic-turtle-actionlib* ros-melodic-turtle-tf* ros-melodic-turtle-tf2* ros-melodic-turtlesim* ros-melodic-urdf*
  ros-melodic-urdf-sim-tutorial* ros-melodic-urdf-tutorial* ros-melodic-urdfdom-py* ros-melodic-velocity-controllers* ros-melodic-vision-opencv* ros-melodic-visualization-marker-tutorials*
  ros-melodic-visualization-msgs* ros-melodic-visualization-tutorials* ros-melodic-viz* ros-melodic-warehouse-ros* ros-melodic-xacro* ros-melodic-xmlrpcpp*

I've seen this happen a few times, and do not proceed with the uninstall. Any idea why this is happening?