When you upvote any content on Hive you get back 50% curation rewards.
Why are you starting this comment off with this? Any logical reason because it sure as hell isn't relevant to your project in any way.
You're voting people who have given you liquid Hive, you're not giving them part of the curation rewards, just their value back over time in the form of small votes over many posts. That's the issue.
Sure you may give some people units for free and that's fine and encouraged with hopefully some oversight on who the receivers are, and sure people gift the units to others but it's still costing them initially and that's how you've made most of your hivepower I reckon.
I don't understand what you think I may not be understanding over your mechanism. It's voteselling with a long-tail, is it not?