There are indeed only a few such firms - but those firms are probably some of the most bulletproof in the entire industry.

BlackLotus hosted stormfront for years, CloudFlare hosts reams of controversial content - wikileaks, the pirate bay, 8chan, etc. They're practically known for it.

Currently at least, it's still quite possible to find a provider who will look out for their customers. In the registrar category there are a few providers who shine, DynaDot and EasyDNS have really gone to bat before.