I totally understand if you need and want an email response from a therapist you're working with. You have found this approach helpful and supportive in the past. I don't think you wanting that from the therapist you choose to work with is "expecting too much." I do think, however, that expecting a response from a therapist who has very clearly stated that he won't respond to emails is not reasonable.

When you met with this therapist, you stated what worked for you in the past and what you wanted now. He countered with agreeing to allow you to email but stated he wouldn't respond to your emails. You both laid your cards on the table and proceeded from there to engage in a therapeutic relationship. Perhaps the only place he could have done more is to explore a bit more about how you felt about his personal rule about not responding. If he had done that and you heard him clearly and firmly state that under no circumstance does he engage in email communication for things other than schedule change, would you gone ahead and engaged in therapy with him?

It's hard to accept someone's limitations or rules of engagement, but reality is, we each have the right to set our own rules. You want the response and he doesn't work that way. It sounds like he might have compromised a bit by even allowing the emails one way. I think you have to decide if you can live with that or you need to do a bit more searching. There are plenty of therapists who allow email communication.