"Nobody forfeits any assets. It's not theirs as long as it's not paid out."

Try convincing a freshly on-boarded user of that. I tell you what, for sake of argument let's call the downvote a sanction. Now, I don't know how you feel about sanctions but they're generally viewed by learned people as an act of war. So if you don't want to think of it as civil asset forfeiture (or theft), think of it as an act of war. And this is where retaliatory downvotes and or flag war come from. Somebody starts it, and then it just continues on ad infinitum.

"I misunderstood the sorting, but I still don't get his that would incentivize professional content creators to spend their time here. They need to get paid, not rewarded by a ranking."

That's the thing, the sorting system is separate. You'd still have the upvote button, but it would be called a Tip Jar. The upsorts and downsorts are seperate, Reddit style. I think this kind of system would create more harmony, less flagwars, and less drama.