The leftists still do this when it comes to "gun control" the idea that "good guys" giving up their weapons means that there will be less weapons for "bad guys" is utterly nonsensical.

That is ultimately what individualism is. Putting yourself into the smallest group possible, while everybody else still teams up against you. No matter how "principled" you might be, your principles could also be the thing making you weak and exposed. Principles are only useful if they actually benefit you in the long term.