Another example of a T needing training/specialization for is BPD. Even though treating PTSD is very similar and has similar symptoms, training in PTSD is not enough to treat BPD. I learned that from ex-T who thought it was enough.

An ex DBT group T also thought he could control a group for DBT that included people with BPD because he ran a men's group before, and he completely failed.

And my fiance once went to an anger management group where the T thought he knew what he was doing simply because he was following a book!

So yes I agree that Ts need training to deal with particular issues. If they don't, they could do a lot of damage (like ex-T did to me)