If you also posted the mod for free, nobody would have a reason to pay for a re-posted paid mod. If you're both charging for it, then that goes into the realm of intellectual property. That's a change that could be painful in a world of previously free mods, but something not uncommon in other places.
It's an app store. The question comes down to: would you rather have an ecosystem of only free (or donation-driven) mods, or would you rather have some mods be paid mods? I really don't think the move to paid mods is as apocalyptic as reddit was making it out to be.
