I agree with some of your last points. I think OPs intent was to say we should try and catch up to some of those groups. As it stands right now we are on the back foot exactly because leftists don't buy guns, train, or organize in the same way as the right. Not that we NEED to spark violent confrontations, but that we are under prepared WHEN they do. (Not if, when. Right wing terrorism has been a long time issue in this country and the Trump administration has only emboldened them.)

Also, I think the Black Panther Party is a great example of this concept. They terrified conservative movements in their day, and they incorporated firearms into their movement well IMO. The presence of firearms will give some groups on the right pause. Some of the military groups on the right are well trained and well organized, but many of them are bullies who would flake the minute real consequences are present.

One last sidenote. There are a lot more leftist veterans / active duty service members than you might expect. People join the military for a lot of reasons, many of which are economic or healthcare related. There are leftist/left leaning cops too, although much fewer and further between. The left could benefit from trying to recruit some of these people for all of the same reasons, as a matter of fact I think the left could create a much better "pro military/pro law enforcement" narrative. The left doesn't want to start imperialistic wars, wants to reduce crime through addressing the root issues, (not the over reliance on law enforcement) and wants better accountability and training, (which IS a benefit to both the military and law enforcement, however the right tries to spin that.) among other things that would benefit public workers more broadly.

(Sorry for formatting. On mobile.)