If we can do wholesale deportations of people we don't like, we can confiscate millions of guns

"we don't like" refers to the (non)sensibilities of the right wing fucks' view of foreigners.

"we can confiscate" refers to major limitations on gun ownership.
~limit the number of guns per person ton let's say, two. Confiscate the rest
~ban certain gun types, such as automatics, confiscate them.
et. cetera