I don't really believe it. It's the big sites that have the monetary backing to employ the dark algorithmic patterns and monetization schemes.
I don't really see much of an issue with the content of the porn if that's what you mean by nastier sites. To me it's more like if you ban cigarettes and now kids are all buying black market cigarettes without nicotine.
Pornhub has banned many videos already. It forbids and deletes any amateur video not posted by the original author (to prevent revenge porn, non-consensual porn, repost of videos since deleted by the author, etc.) and also forbids certain keywords related to non-consensual porn like rape, sleep.
Mindgeek (company owning Pornhub and many other porn websites) are by no mean a company respecting sex workers as good as they should but they are putting an effort to stop nasty shit from their websites if only not to be banned.
So I would agree that Mindgeek websites are better than others. Not good enough but better.
I don't really see much of an issue with the content of the porn if that's what you mean by nastier sites. To me it's more like if you ban cigarettes and now kids are all buying black market cigarettes without nicotine.