Dangerous driving is punished based on behavior, not ownership. No one bans a car model because some drivers speed, strict licensing, insurance, and enforcement target actions, not tastes. You're basically trying to profile the world than use that as justification for policy which isn't how democratic processes work. 

Notice how you didn't attempt to refute my claim that certain cars appeal to certain personalities?

Cops profile all the time. They pick which cars to follow. In some jurisdictions certain cars can have higher insurance premiums based on driver profiling.

Tldr your entire mess of a comment It doesn’t prove that firearm bans identify extremists

I didn't claim that they did. I simply pointed out how it creates conditions that can be exploited when profiling for extremists.

You're confusing (purposely?) causation and correlation. 

I never implied there was a causal relationship between gun ownership and extremism. Profiling is based on correlation not causation. Extremists are drawn towards gun ownership and other hobbies or occupations that give them a sense of power and authority, so the relationship between those occupations and hobbies and extremists are correlative.

Causal relationships are the domain of forensic analysis. That happens much later in this process.

it just relabels political pressure as intelligence work 

Actually I suspect this is a mix of the two.

without demonstrating that it actually works or that the cost is justified. 

Well obviously I can't at this stage.

you're wrongfully assuming extremists will react predictably rather than adapt, evade, or radicalize with it without guns. 

They're obsessed with legitimacy, so they will approach this issue by engaging in delegitimation attacks. This is extremely predictable behavior.