It is the assumption that anything urgent or critical in nature is not communicated via email or text. And you knew he wouldn't answer because that's exactly what he told you he'd do. It is a boundary thing and a way for him to set a precedent. It might sound cold but I think there is a lot of confusion and hurt when Ts answer some emails but not others. Or they answer in a way that isn't what he client wants (since emails and texts are notoriously open for misinterpretation). Consistency is important, even if it feels lousy. I bet how will probably bring it up at your next session.

I do agree with others that you should find a T meets your needs. Your present t is not going to change how he practices therapy - if he doesn't email he doesn't email. If it's that important then you probably should look for another T.