Maybe you don't even know what you are doing?

just because you see minnowbooster while u spy my account and wallet does not mean I'm selling my upvote. It is just set to automatically claim rewards. Geez did you see that I have my sp back long time ago after realizing that I don't like to sell my upvote.

There is one way to earn rewards from minnowbooster: delegating SP to it. You delegated SP to it earlier, later undelegated, and this SP has now returned.

There is another way: letting them vote with your account. That's most likely the way your vote ended up on the comment spam farm mentioned above.

Take a look at https://steemd.com/@diabolika, there you can see your votes and compare to which votes you made manually.

The remaining ones have been made by minnowbooster (you granted posting authorities to minnowboster, this gives them the ability to vote with your account). So they are selling votes of your account and you get rewards for it.