That was my point. People are so desperate for a solution to their problems, that they are willing to even go to the Dark One for help. Regina betrayed Jefferson once, and yet he was desperate enough to go with her again–until she repeated her old mistake. And as for Jefferson freeing Belle, he didn’t seem to really want to get close to Rumpelstiltskin. He just told Belle to find him (and he probably gave her directions to his place) and that’s it. Plus, he only allied himself with Rumpelstiltskin after having done the former a service–he wouldn’t dare go to him for a favor, knowing he would have to pay a price. He wants Rumpelstiltskin to be the one that owes him.
As much as Regina may have made many people miserable, we don’t really know how she treated her remaining allies. She may have been very generous to them–King George was made a DA, and Doctor Whale (who may or may not be on her side) was made a doctor.