I'm actually working with Tor Project to fix the captcha/etc. problem; it's not intentional, and we're trying to figure out a way to special case Tor exit nodes and other shared IPs to prevent accidental blocking.
(We have the advantage of only really caring about http/https through Tor, so we can do more advanced heuristics for abuse, blocking URLs, etc.)
(We have the advantage of only really caring about http/https through Tor, so we can do more advanced heuristics for abuse, blocking URLs, etc.)