I think I know what I'm saying, and you clearly do not.
Do I think a "militia" should be allowed to patrol the streets of Kenosha while armed? Yes. The law allows this.
Do I think it is a good idea? No, it's fucking stupid. I'd prefer if they just patrolled the streets with their cellphones out, recording what they want and submitting anything they feel is a violation of the law to police. I think allowing the open carry of weapons in public is stupid. It's not illegal in Wisconsin though.
Standing guard in front of a property does not make you a vigilante. If that were the case, the vast majority of security guards would be vigilante's as the vast majority don't actually have any more legal power than a regular citizen. Furthermore, vigilantism isn't actually against the law in most places. Acts one carries out in the process can be. Setting up a community watch, by your definition can be vigilantism.
The laws set up are dumb (and specifically to Wisconsin, their sloppy gun laws for <18). But they're the laws Rittenhouse will be judged against.
I can be for saying he will get off based on current evidence and still be against vigilantism. They're not mutually exclusive.