You’re not wrong, but not normalizing political assassinations is about quite a bit more than “decorum”
This is like saying “well this guy is doing date rapes so I don’t see why I can’t joke about raping his sister”
The answer is 0 assassinations. The answer is the rule of law. I actually 100% agree with you that most of the political left has its head in the sand about the urgency of coming to grips with what the right wants to do and stopping it, but “let’s go ahead and have the civil war then, what’s the worst that could ensue” is about the worst possible take and strategy that you could employ in response