" In fact, the very fact that we have patent trolls that can run around and sue business after business after business for the same patent, while the businesses have no evidence that shows they have communicated with each other about the patented subject, ought to be proof positive that the patent is obvious and shouldn't be patentable."
Whether the person suing is or isn't a patent troll is irrelevant to your argument. You are basically arguing that if lots of people have done something without colluding it must be obvious. Not so.
I recommend this piece on hindsight bias. It is an extremely well documented fact that things rapidly become obvious after the fact.