The problem here isn’t people demanding access to your body, but framing the discussion as though that was the issue. IDGAF about personal history. If the thought of dating a transgender person gives you the willies, you have a problem with transphobia. Deal with it. Saying that transfeminine people are demanding sex misrepresents the situation in a way that reveals the person making that representation thinks of transwomen as men.
If you don’t want to have sex with someone or date, the reason doesn’t matter. Don’t have sex. Don’t date. Say no. That should should always be enough. You don’t owe anyone any explanation. If the reason happens to be personal transphobia, please deal with it on your own time. Don’t try to explain it and don’t ask for the person you’re rejecting to be the one to try to make you feel like a good person despite that.
Being transgender doesn’t mean that a person is automagically going to respect limits and boundaries. There will be people from any walk of life who will abuse the communication tools of their culture to try to manipulate people into sex and other forms of involvement. I’m not saying that never happens. I am saying that is not a pervasive issue, but it gets cast as such in way that is harmful to the dialog that needs to happen here. If that’s not where you were coming from, great. Please don’t buy into their language.
The original context… Lesbians who fetishize AFAB genderfluid people as butch lesbians irritate me because they aren’t respecting genderfluid identities as authentic. You don’t have to have sex with someone who was AMAB to be authentic. Just understand that selective attraction to a form of genitals is a fetish (with no negative connotation intended), not an attraction. Own it and don’t behave transphobically in relationships with or attractions to those whose trans identities you find conditionally desirable.
To address your point better… I’m not in a great place to know what conversations are happening in the masculine counterpart to this sphere of activity. I shared what I’ve seen, which is what those in my life have shared with me. I’m not a consumer of transmasculine culture, so I don’t expect to know what is on Tumblr and other venues for them. I know it happens and that it happens in ways that deeply affects those involved. I know LGBT social apps have different categories for trans and cis men and for trans and cis women. I know cis gay men often have “No fat. No trans,” or specific “size” requirements in their profiles that are hurtful for gay transmasculine people to see and oppressive in experience. It’s hard to imagine this happening so pervasively without explicit dialog about it.