To me it's all a matter of the percentage. If you're splitting your vote power 50/50 between self and others, I'll be ok with it, though I'd prefer less self voting. As it creeps above that I'll start to grimace, and at levels of 80%+ self voting it's just egregious. 
It's not illegal, yes the code allows it, but it's a matter of community standards and etiquette which we all organically form by our behavior. No one can stop a person from self up voting 100%, but no one can stop a person from posting plagiarized content either. What we do control is the community reaction to the situation.

I feel like the bitcoin miner comparison is somewhat flawed. I think a better analogy is to consider ourselves shareholders. I mentioned in another comment elsewhere, that if you can show me a company where the shareholders voted that all profit be paid out to them in the form of dividends, completely foregoing spending on  employee raises, hiring, development, improvements to infrastructure, etc... and that company is thriving... then I'll change my opinion.
That's essentially what 100% self voters are doing, and they're relying on other more rational voters to pick up their slack and keep the overall organization running while they continue to reap profits that others are foregoing for the sake of the business and a more long term vision.
If heavy self voters consider themselves short term investors and follow this valid profit strategy, it's up to long term shareholders to down vote them in the interests of the whole. If people feel the self voting practice is harmful to long term success , it's ROI needs to be mitigated and made less profitable.
We force people to self tag potentially objectionable content with the nsfw tag so that it can be properly filtered. If they don't they'll have that content filtered for them through downvotes. We do this because we recognize that having such content clearly and randomly visible on the site would be a huge deterrent to it's growth and success. There is no code, no rule prohibiting people from posting porn under the tag familyfriendly. So to me the "it's part of the code, it's allowed" argument doesn't fly. 

Of course that kind of depends on how "allowed" is being used. If it means that  we should leave heavy self voters to their own strategies and devices then I disagree. If however someone takes the "code allows it" stance and equally agrees that if self voters begin to be flagged into oblivion, they are equally ok with that, then I respect  their viewpoint because it's consistent and based on community consensus.