I heavily agree on your notion of this camp mentality, this is not how political discourse should work. It is way too over hostilized. Here is an interesting article from a self-proclaimed lefty on that topic. I see it similar. Only because I disagree with someone should not mean that I hate them. We should embrace our differences.
As a lefty myself I condemn assassination - it is a trademark of hidden big power. I agree with you and Rand Paul on being armed against tyranny, it is not about killing some politicians in the street, it is about having the possibility of a revolution and a coup d'etat.
However we got the military for that. The military and other armed forces like police tend to get a bad reputation, but they are also humans. Being in the german military for 1 month hugely changed my view on it. Even with 'political talk' being a restricted right as a Soldier, most of the higher ups and comrades voiced their discontent with the current war and political situation as a whole.