Truly anonymous voting is a non-starter on this blockchain, but you might be able to convincingly argue for a feature on steemit.com that would allow special categories of post creators to hide a post's voters.

Honestly, though, it seems possible that you are misinterpreting the reasons for the voting patterns you identify as problematic. Personally, I vote for NSFW content - including yours - only when it appears to add value to this platform. When something does not strike me as a value-add, I do not vote for it. If lots of people also vote like this, maybe some of the content you see as undervalued is really just correctly valued by a bunch of people with slightly different tastes than yours.