I agree censorship of ideas or opinions is a bad thing, but if what he says is true, that the sub was being essentially rendered unusable by sockpuppeting, trolling, organized downvoting (which is also censorship, BTW) or other abuse, then what option is there but to clean it up? This is not a specific /r/bitcoin point, it's something that dates back to Usenet times, and applies to every forum since.
I don't know who is telling the (most) truth here, I have no idea, because I don't read that group and don't really follow Bitcoin (or even Reddit), but I do think it's fairly absurd that Bitcoin (a supposedly democratic, decentralized technology that nobody owns) has always had what are essentially a handful of very powerful 'official' channels and representatives, with enormous influence, and AIUI major forums, including /r/bitcoin and BitcoinTalk, are actually owned by one single person (perhaps the parent of your post).
But nobody in Bitcoinland seemed to care that much about such "dictatorships" before.