I don't view either vote bots or leased delegation to be inherently wrong. Both of these are ways to temporarily magnify voting power as opposed to buying the stake directly. It can be viewed as a "rent or buy" approach to hive power.
But the problem, from my point of view, was that most of the votes cast by vote bots were often voting on poor content and was typically just self-votes by people looking to directly profit from an imbalance between what they received via author rewards versus what they paid to vote bots. The blockchain economics before the EIP changes were terrible and incentivized self voting by posters that had no long term tie to the ecosystem's performance.
We forked out the vote selling bots.
When do we address the vote selling through leasing?
The vote selling bots weren't forked out per se, it was just users deciding to downvote them (i.e. "The crowd enforcing its will").
The EIP changes just made it more economical to do that (change of author/curator rewards ratio disincentivized vote bot usage some and free downvotes did the rest. These same changes potentially impacted votes cast with leased hive power as well, which begs the question, why hasn't it?
My guess is that people aren't as bothered by the way delegated hive power is being used to vote on posts in most cases nowadays. If someone did lease hive power and started using it abusively, I suspect it would draw downvotes. Just the same way it could happen even with staked hive power being used abusively.