'Dick' itself isn't bad!
The word used was 'girldick'. I can pull it up. If they just said dick honestly it would probably be fine? Girldick just has harmful connotations because it is specified it is a dick, on a girl, and would be assumed that it's part of the attraction. The word 'dick' itself does not carry this second meaning. It's just not a neat phrase to say to a trans woman. They know they are a girl and they know they have a dick. Just because they are pre op doesn't mean it needs to be discussed.
I'll grab a screenshot, will attach in another reply.
Edit for more clarity