As pointed out by blibble, the blocking is almost certainly due to Mr. Angry having got himself onto a list of open proxies somewhere along the line; any effort directed at tor, whether masking, restricting, or outright blocking, is in my experience always aimed at exit nodes only - because there's simply nothing to be gained by blocking relays.

Note that I have no particular insight into this specific case, but have opered on irc.perl.org for some years now (and was freenode staff for a while) and am working based on a >95% correlation with previous similar cases that I've dealt with myself.

Odd, my experience differs.