> So, I buy tons of IP from companies and individuals willing to sell them - the more generic, the better. I then troll around looking for companies that make products that might fit some of the patents I just bought.

That fits my understanding of patent trolls' behavior. What I still don't understand is, why is this seen as worse than e.g. a streaming service like Funimation/Sony buying up exclusive rights to anime that other entities have created, and then Funimation/Sony sues other website that continue to stream those videos?

My best guess is that because the USPTO has issued patents that seem unjustifiably broad/vague, it's harder to be certain that you're not violating some patent, than to be sure that you're not violating someone's copyright. But if that's really the reason, it still seems to me like the real villain here is the USPTO / U.S. Congress. Because (to my current way of thinking), they created the business landscape that rewards this kind of behavior.

Patent trolls are exploiting a bug in the patent system. They don't buy patents that are actually novel and useful; those are too expensive. Instead, they buy 100s or 1000s of patents that are vague and/or obvious. These are cheap to buy because they don't have much of any value on their own. They bundle dozens of these together, find lists of companies somewhat related and send demand letters to all of them. Simply defending the lawsuit will cost more than they're asking for in the demand letter, so many companies just settle and write a check.

But the trolls and the government aren't two separate, independent groups. Whenever the patent office tries to tighten things up, the trolls go out and buy enough congresspeople to let them do business as usual. Successful business people have the power to get Congress to make things even better for them.

Legal != moral

Just because you can exploit the system doesn't mean you should.