And because I'm lesbian and livid at that stupid tweet:
There's no such thing as 'cis', women are not a subcategory of the female half of the human race, and while you're entitled to your opinion, no, I don't accept your personal view of reality as truth.
Please don't call me 'cis' if you expect me to respect your personal language choices: this is either reciprocal or there's no dice.
Gender does not define homosexuality, sex does. I get this is really upsetting and inconvenient to you and limits how real you can make your choice of personal identity, but other people have rights too, and you don't get to remove human rights from people and forcibly redefine them, their lives and their bodily autonomy for your own self interested benefit.
If you're talking about my right to bodily autonomy then you've forced me to the discourtesy and I have the same right to speak clearly that you do: the facts are that transwomen are male. They will always be male. Their gender identity and their biological sex are not the same. I appreciate this is an upsetting reality, but in some situations, such as homosexuality, sex matters to some people. Having to deal with other people having boundaries you don't like is a basic adult skill.
Yes, genitals matter in sex to many people. No you don't have a female penis, there is no such thing. How you name it and view it is your choice, but you are intentionally redefining language in an attempt to persuade and coerce unwilling women into sex.