Your own comment would have been a lot better without its first sentence and that "idiot" clause :) I didn't find the parent's comment rude or trollish.

It seems clear that therapy can help people. It also seems clear it is not a panacea, and that it can depend on both the person seeking therapy and the therapist, as well as the reason for therapy. It sounds like the parent was sharing their own experiences, which are just as valid as your own.

If we elevate therapy and therapists to be beyond criticism, all we end up with is a cult. Take the parent's comment on credentials and licensing: I'm sure that we want our therapists to be licensed, using evidence-based techniques, but that doesn't mean all credentials are created equally, or that because someone has credentials automatically means that they can be helpful to you personally.