Ugh, yeah, it does sound like you need to keep searching. I feel like "Why did you become a therapist?" is a pretty common, basic question. I don't see that being a boundary compromise at all. He just sounds too defensive and closed off.

I will say that my current T was pretty closed off with boundaries early on--like I could have seen him writing a similar email. I think of an early one where he talked about why clients need to refer to him as Dr. [last name] and not [first name]--when I was actually asking why he referred to my marriage counselor that way, when I referenced him by his first name (not about him at all). And some of those boundaries caused major conflicts at times and put a big strain on the relationship. He has eventually come to relax them quite a bit, like he seems like a completely different T now. But that was over the course of 3 years, which is a long time. So I think you're making the right choice to cancel.