You have to judge orgs by how much money they have. Kind of like you give a pass to a really low-budget movie, and complain a lot about a blockbuster that had a huge budget.
Bellator doesn't pay as much as UFC but no one complains about their payouts because Bellator doesn't have revenue close to UFC.
One Championship has/had money behind it but very little revenue I'm guessing, so at some point they can't pay fighters as well as they used to. Maybe their contracts suck too. Most promotions in the fighting world, like most boxing promoters, are going to be sketchy and screw over the fighters, that's a default condition. It's a surprise when they treat the fighters well.