I'm a man and so far this has happened only with other men, but I'm genuinely baffled as to why some people do this. It has happened thrice so far in 3 different work settings:

One was a fifty-ish coworker who, 3 minutes after knowing me started a monologue/rant: 'I'm very Christian, there are too many migrants and refugees in this country, when their wars are over, we have to send them all back'. Kept repeating the 'very Christian' part quite often and talking about his conservative wife. I sat there, not knowing how to react until he said 'but let's not talk about politics'. We parted ways. I didn't work with him after that.

Another one is even better: no more than 4 minutes after knowing him on our first shift together: 'democrats and unions are useless (this was working in an unionized hospital where the union got us a raise, including his), there are too many Arabs in America, if Biden keeps letting migrants in, there's going to be another civil war, when Trump wins everything is going to be better, you're lucky to be only part Mexican, because you don't look too dark. When I was younger I was a right wing extremist, but not anymore and I'm not racist, because I'm married to a Croat.'

Speechless as well. How do I react to that?

The third one was not so unhinged, but opened his wallet to show me pictures of his service in the navy and then started to talk about his health issues. 20 minutes in our first shift together.

Why do some men do this?

Is this a way to test the waters to see how ideologically similar we are? Not everyone is going to think like you. Why alienate coworkers?

I'd never talk about my health issues with a person I barely know. You put yourself in a position to be exploited.

Do only older white conservative men do this?