I will make some assumptions, seeing as everyone else is doing so on here. It’s all speculative though.
I suspect that if you are a core member of the RF then poor mh is frowned upon. They live by the traditional values of never complain, never explain, stiff upper lip, and keep ploughing on whatever the circumstances.
This probably clashed horribly with the view of someone who was essentially Californian in outlook where you can obtain therapy for your cat if you want to.
I suspect it was more the fact that they disapproved of her needing psychological support in the first place, and they feared the story getting out (after all therapy would probably involve airing problems and grievances) and they were worried about privacy issues more than anything else.
Even if that’s incorrect, when you have recently married in to a family, and just given birth, and you are trying to fit in, it could potentially be very uncomfortable if you are suffering in some way and the family either don’t approve or don’t understand the reasons behind your poor mh or think they are justified. And in those circumstances, you might not want to make things more difficult for your dh if he is lower in rank in the hierarchy of those who set the rules.
These are just my thoughts. I won’t be responding to the usual ten or so posts telling me how wrong I am.😀 And no need to post photos of burning matches either. 😀