It is not you. They register and then post spammy topics in the forums. You never see that bit because the spam filter locks it away before it ever gets published.
I’ve been hesitant to add barriers to joining because they will affect legitimate new members too. However, if this keeps up, I might have to do something. I recently blocked all of China and a few other non-English speaking areas where a lot of spam comes from. It worked for a few days but then the spammers started using IP addresses from other countries.