Imo it rlly comes down to the expansion of the term lesbian to mean “non-men loving non-men”, which definitely includes transmascs if they want to be included in it. While trans men specifically aren’t necessarily included, I think that’s why we’ve developed the he/him lesbian category for exactly what you’re saying. Trans men can absolutely be sapphic and experience love in a sapphic way, which I think is better described as being a he/him lesbian than a lesbian trans man