It's quite often a pre-emptive strike - because some people assume I'm arguing as a white male Trump voter in his late fifties living in the deep south. When I point out I'm British they get flummoxed. Being British isn't a secret.

But everything else is, because if your opening gambit is to attack the person, you aren't really debating the topic, you're trading insults and questioning integrity at source by virtue of demographic - and that's not conducive to reaching consensus.

And I just got bored being attacked right out of the gate. :o)