Because it would be a monumental waste of time and money. Even if you could track down the overseas operators doing this, there's not much damages you could sue for, and alternatives would just pop up in their place.
I know US people who do this for a living
A few years back a bunch of influencers were fined for doing just that.
Their main activities were click botting and general social media marketing (day job was in SMM analytics).
But if you're already there with the automation for thousands of accounts and the knowledge of what an account looks like why not also put some to ripen for 9 bucks a comment :)