The folks taking meds are likely already prohibited from owing a firearm.
Not even close. When you say "Mentally Ill" you cast a very broad net. The APA defines mental illness as:
" Mental illnesses are health conditions involving changes in emotion, thinking or behavior (or a combination of these). Mental illnesses are associated with distress and/or problems functioning in social, work or family activities."
That is a much broader net than what we are talking about here. Someone who suffers from depression or anxiety and takes meds, that person would technically be called mentally ill. Someone with ADHD is in fact mentally ill. Someone who does not like to socialize much could be called mentally ill.
The people who are mentally ill and commit hostile acts against others are a tiny fraction of the total, yet we speak about taking firearms away from the total. That is no different than taking guns away from everyone because a tiny fraction will use them inappropriately. If you can do that to a subgroup then you will gain the argument to do it to the whole.
