I think it's perfectly fair to require 200 rep to add a link.
It's not a big deal if you can't put your link there, and we get tonnes and tonnes of spambots. It's a big problem for the site, and the more spamlinks that make it on the site the more likely search engines are to downgrade the whole Scirra site as a "dodgy neighbourhood". This 200 rep thing will probably just remove the problem entirely, at minimal inconvenience for regular users.
(All forum links should be nofollow'd as well, perhaps until 200 rep)