How? Compare to email spam where the cost is zero. Is that in any way better than a world where it takes substantial capital to send email spam?

Lower cost = more patents = more patent trolls = less innovation.

Maybe they think it'd be a good thing because it would eventually phase out patents?

Any company that tried to bring a lawsuit for patent infringement would potentially face dozens of suits for their own infringement, a kind of legal mutually assured destruction.

That would lead to even more centralization of email than we already have, and that's a bad thing.