He's a brilliant guy, but this is a terrible example. Worms can't communicate with us, so obviously we're not going to try to have a conversation with them. If we found a worm-like species on another planet and their vocabulary consisted of nothing more than a couple hundred words, I can guarantee you we would stop and try to have a conversation with them. If a vastly superior race came upon us and we were the first species they ever found that they could communicate with, I'm pretty sure they'd do the same.
Tyson's entire point is that alien life, even life that appears to do things we associate with intelligence and language, may be so different from us that we are fundamentally unable to communicate, just like us and worms. What if their language is undetectable (or even absent) and their intelligence is inscrutable? He's assuming radical differences rather than assuming any similarity.
