The issue with dropping UDP is that DNS uses UDP in most implementations. Unless you have no need for DNS on your network, you might want UDP packets to be not dropped completely.
Ah, that a web host might want to host their own DNS in house (maybe for ease or cost) is not something I considered (I outsource DNS as it is sufficiently performance sensitive you really want to AnyCast it against numerous networks, and there are people that specialize in that). As a client you can just use TCP for DNS. (Again: I am not a host ;P. Thanks!)
