I did a quick (unscientific) test.
https://bitcointalk.org/index.php?topic=5486210.0Complete nonsense post, and I got two replies from people with signatures who obviously didn't even read it. I haven't been able to have a contributing conversation in a few years due to all the paid to post spam.
Is a topic in the Off-Topic section really a good idea for gauging the quality of the answers on the forum? It's not
la crème de la crème that generally posts there. If I want to judge how open-minded Americans people are, I'm not going to do my test at a KKK reunion.
You should maybe do the test in a section related to BTC (technical, mining etc..etc..), I think the results would be different.
I was personaly able to have multiple interesting conversations despite the signature campaigns (even if I agree it would be better without some specific spammers)