I don't think it's premature, I think their plans are evil, so I react to that the only way I can. Nothing premature about that. If Google were to think about doing this, I'd do the same, to send a message.
Hypocritical because you think it wrong to degrade a search engine's index in return for money... but degrading a search engine's index to send a message is fine.
So even without the money, a search engine messing with another search engine's index seems wrong. Me as a content provider, I have all the right in the world to block anyone. But me as a search engine, I shouldn't actively try to mess with the index of another search engine.
There's a big difference between me deciding to block a search engine on my sites, and a search engine paying content providers to block another search engine. I mean, I may still be wrong, but there is a big difference in degree, right?