Accounts with high-rep can downvote anyone with lower rep than them below (0) which automatically hides all their posts and comments and breaks any links to their posts and comments.

It doesn't break any links, and the fact that it's hidden is completely contingent on the front end/block explorer being used. Moreso it doesn't stop or hinder them one iota from continuing to downvote and effectuate the only metric that means jack shit, unlike reputation which has always been gamed, broken and never had any weight outside a value for front ends to interpret.

but they couldn't wipe out ENTIRE ACCOUNTS.

Please.