In my experience, therapist non-disclosure undermines trust, safety, and healthy relating, just as it would in any relationship.

In any other context, the behavior of OP's therapist would be considered anti-social and would arouse suspicion, not trust.

Just because therapy is "all about the client" does not magically change the realities of human interaction.

The more something departs from a model of basic healthy interaction -- openness, mutual honesty, authenticity, etc -- the more it ought to be questioned in my opinion.

I think OP's concerns are valid and precisely the right concerns.

I too felt an unhealthy level of exposure. At gut level i knew it was unhealthy, but squashed these feelings in favor of therapy orthodoxy that was preached to me.