Did your speech therapist meant dressed up or just dressed as you're living? Some speech therapist won't work with (trans)women until they're fulltime and will always come to the sessions as women. They feel it helps with the authentic voice the client is trying to develop. It's not just how you see yourself but how you present yourself and relate to the everyday world. So, they're reluctant to work with a (trans)women who presents as male.
While you can argue the issue, it's your choice if you want their help or not, to abide by their requirements or not. Granted it's not necessarily fair or right, after all an actor may seek a speech therapist for a female(-like) role and want the voice, or some such situation. But in the case of (trans)women, it's about the everyday world we live in that matters to them and they simply want to make that clear.
And yes, mine, when I went, made the same rule. I left because of the cost didn't fit my budget at the time. I'll go back when it does, and the requirement doesn't mean anything anymore.