The internet is decentralized, which is another way to say lacking in meta-incentive capabilities (e.g. cannot resist incentives for long, unable to influence or modify the set of incentives being applied to it), which means it will always fall prey to the dumbest race-to-the-bottom traps.
I'm on Dreamwidth. I have regular conversations with a variety of people who I've known for years, many of whom I have no idea what their real identity is. There is almost no spam, because the site owners take spam seriously, and also because you get total control over what you see.
If you look you can even find research arriving at the conclusion that non-anonymous posts tend to be more toxic.