That makes sense for posting, where Tor users often get a CAPTCHA etc, but I can't even read it. If I go to any site on SE, I'm hard blocked, I can't even fill in a captcha to bypass it.
Loading CAPTCHAs is still very expensive, and is not an answer to large-scale DDoS attacks. Those have to be handled higher up the stack, usually at the proxy/load balancer level.
I tried a new tor a few times, they all got blocked.
I've tried to create new circuits, changing IP addresses, and they are all blocked.
That’s a very convenient excuse, if your goal is to collect more data sell to advertisers and anonymous users annoy you. What next? There has been a lot of spam from people wearing clothes, so everybody needs to be strip searched?
that's pretty much how safety regulations at airports work. Stackoverflow perhaps hired a prior airport consultant for security.