The reason why Basira considers Jon’s feeding worse than Daisy’s is plausible deniability. Or lack of it, in Jon’s case. You also have to remember Basira herself used to be a cop. Daisy’s violence is justified because they believed she just intended to solve crimes and punish the guilty (a mindset I don’t support but Basira shares it) but Jon is just traumatizing people for the sake of traumatizing them. Death is, of course, a worse outcome but what Jon does is also incredibly traumatizing and violating. His victims are forced to relive that fear they experienced over and over and over. And Basira who is doing a cost-benefit analysis sees it solely as harm as the only one who benefits is Jon himself. She can’t confront the harm Daisy caused because that would require confronting the harm that she herself caused solely by existing in the system.
And another point I haven’t seen brought up: both Melanie and Basira know what it feels like to be haunted by Jon, to relive those terrible moments while being watched by Jon. They weren’t hunted by Daisy. Thus the terror caused by Jon is more tangible to them, more real almost. They know what it feels like.