@Notgoingononlyfansyet "It is literally not possible for you to judge an illegal action positively."
Untrue. In Iran, marrying an 8 year old girl is legal, and I can judge that as being wrong. Smoking marijuana isn't legal in many countries, but I can be non-judgemental about that and think it should be legal. In addition, kicking a dog may be illegal, but I have no doubt some people (likely dog kickers themselves) wouldn't judge someone for doing so.
So no. Personal judgement is very much entirely separate to legality.
"And I DID suggest that he go to therapy to explore where the kinks came from and that she go for support in refusing to be involved and help with the issues it brought up FOR HER"
'Refusing' to be involved? What a word choice. Regardless, it doesn't seem like she needs help, or that it's brought up any issues for her that it wouldn't bring up for anyone who's not into it and is suddenly confronted by it. It's his issue, she's clear she's not into it, so now it's his job to stop badgering her about it, and seek therapy to figure out whether it's a deal breaker for him or not.
You said, in regards to her feelings, "It’s always worth finding out why something bothers you, I think" as though you think there's something wrong with her for being bothered, when 90% of the world would be bloody bothered! It's normal to not want to be pimped out for free as part of your partner's kink! There's literally nothing to find out.
"If she went to therapy to help get past an affair, you wouldn’t say I was pro affair that the affair was okay, or that only he needed therapy for it."
If you said they should go to an affair-positive therapist to explore it, I might raise an eyebrow!
I think the issue is that it seems you think she needs therapy to work through why she doesn't want to do something that 90% of people would never want to do. Whereas in reality, she's drawn her boundaries and is perfectly happy with them - her concern seems to be how important this kink is to him, and whether he might already be acting on other kinks without her knowledge. So if anything, he needs to be told to figure that out in therapy, and then come home and be honest with her.