If a person identified as a parent without having any children they cared that would be odd I agree.
Female and male are biological sexes.
How is it less odd to identify as the sex you empirically are not and never can become (medically speaking), than identifying as a parent when you do not have a child?
There are distinctions between lesbians and males-who-identify-as-lesbians. I use that clunky phrase deliberately because there is no such thing, to my mind, as a male lesbian.
But trans women with female partners are effectively in very similar relationships to lesbian relationships so it's not so odd.
This is a heterosexual couple, biologically speaking. (It's a sticking point from a personal experience that is too revealing to go into on this forum, so apologies for not expanding on it.)
So to use a more general example for discussion, I'd like to ask you how Alex Drummond, a previously heterosexual male who transitioned in middle age, is a lesbian now? What barriers did Alex have to overcome (structural, familial or internal) to accepting or expressing a sexual orientation towards women? Does Alex "draw out the inner lesbian" in women?
If a trans woman is legally a woman and has a female partner and they want to call themselves lesbians that's fine by me. No need to get all would up and start going on about rape culture.
If you don't think it's a problem, that's great! Genuinely. Glad things are going so well where you are. 
I agree with other lesbians who think it is of serious concern. I've thought about the issues, argued and gone over logically what I am seeing for a long time. I'm quite solid in my opinion, as a consequence. I believe we should have a right to speak about our experiences and thoughts.
Is there a space where we may do so, without being called hateful or disbelieved or accused of hyperbole or needing security or having to prepare for attempts to shut down our meetings?
If so, where?