I realize that Gabon isn't the US, but having something taken away before any crime is even committed. That seems a bit extreme. What's next, pre-crime units?
My understanding is that his domain registration was invalidated or revoked because he made a public statement that he would use this domain to circumvent anti-piracy laws. I'm sure it's in the Registrar's TOS that using domains for criminal enterprises is not allowed.
Seems like a less extreme course of action would be to just send him a warning that, should he do so, his domain would be revoked (possibly without notice).
Though, as someone pointed out, if you follow the purse strings you hit Vivendi which is deeply invested in copyright. Seems likely that someone realized that they had access to kill his .ga domain, sent out the relevant requests, and extreme (rather than measured) action was taken.