There was a bit of discussion on the HIVE discord about selfvote recently too that I was involved in.

I've always seen it as Self-voting is largely a community consensus rule, It's selfish and greedy but it's allowed by the chain.

My personal feelings on the matter is that self voting should be blocked at the very least on the front end level and that a VERY CLEAR message that selfvoting is not allowed be sent.

It's bad user experience to be able to do an action but be told to not do it because it's bad when you are still able to do it. Either block it completely or educate. Neither we seem to be doing.

I'd had thought blocking at that chain level, rejecting accounts that vote on posts they own would be best but one downside is this is bypassable by simply delegating or having the bulk of your HP on another account and upvoting.
This makes it more difficult to detect actual abuse in the latter setting which is likely why it's not really been implemented.

The frontend level is the next step, this will prevent and send a clear message to the vast majority of users (assuming all frontends implement it) that self voting isn't allowed but again your own frontend/bot/etc and you can freely selfvote.

With this scenario you don't really have a detection issue and you kinda naturally filter out a lot of the more innocent users who might not know any better. Giving a better user experience to normal users and those who want to abuse and go out of their way to do so will be easier to see imo.

It's a annoying messy subject that honestly the worst part of it all is the mixed messages and poor user experience it generates.