As the mom of a trans kid…it WAS offensive, but as you weren’t trying to be offensive and were trying to be sensitive, I was okay with it and think you have the right to say what you want (and be wrong).
People saying it wasn’t offensive I imagine may not be trans or have trans children. My daughter and I do make concessions for people like you who are offensive on purpose. I didn’t have the energy to go into it with you in a way that would be respectful and so I just didn’t.
But then again, anything supporting the notion that trans women can’t be in women’s sports is a transphobic view (doesn’t make you transphobic), and is very offensive.