[UPDATE] I chatted with the top admin of @steemmonsters over the past 24 hours, and I believe - to your liking - they saw the logic in discontining the "upvote service", and have made the following post explaining this :
https://steempeak.com/steemmonsters/@steemmonsters/content-upvoting-policy-update
I offered some suggestions on alternatives, and it appears that the solution that they have come to is in lie with what I was thinking, in general.
My main reason for contacting you directly on this was NOT to have you reverse the downvote (which they have now compensated for), but instead see if there was a way that I could discuss the issue PRODUCTIVELY so as to then discuss some options with SM admin. The response on your end was (in my opinion) certainly lacking in that regard, but luckily SM admin was professional enough to solve the problem.
While I disagree that ALL "paid upvotes" are "bad", I can definitely see the logic in how MANY of them are counterproductive. So hopefully, your mission of LOBBYING the larger dApps to avoid "paid upvotes" has been considered a success in this case, but you may find that some more "strategic" communication may get you to your goal more efficiently, and with less "collateral damage". Just some advice from someone who has the universe on his side ... Good luck...