There isn't a way. As AI improves bots become increasingly indistinguishable from humans. All this does is rely on the fact that bots tend to use different browsers and behave in different ways than humans. But that can be fixed.
But it doesn't matter. If a human user spams tons of links in the comments after creating 20+ accounts, who cares if they are a bot or are doing it manually? I believe that websites should instead use machine learning like this to detect the bad behavior itself, rather than try to determine who the user actually is.
