It's the No True Scotsman fallacy in play.
Acceptance without exception is the Stonewall motto. This may have started out with a different meaning, but is now used to argue one does not need to suffer from gender dysphoria to be trans, one does not need to medically transition to be trans, one does not even have to endeavour to present as the other sex to be trans.
Non-GD, non-med, non-op males externalising feminine stereotypes are traditionally known as crossdressers (Eddie Izzard for instance).
They are for all intents and purposes indistinguishable from the Non-GD, non-med, non-op males externalising feminine stereotypes who also identify as trans.
The word transgender was according to some sources coined to include the latter under the original trans umbrella which originally only encompassed transsexuals who are defined as suffering such severe GD that they seek to medically transition and to have genital surgery.
However without talking to the triple-non-type of male, it is actually impossible to ascertain whether they are mere crossdressers or transgender.
So, what to do? Easy to define the difference one would think were it not for the habit of crossdressers to assume a feminine persona, complete with name change and identifying as a woman while they crossdress.
Still, not a problem one would think, let's make the definition dependent on consistently identifying as trans, right? Eh, no. Not anymore. Gender fluid is valid. Pippa Bunce is valid. Non-binary male identifying as trans is valid (as in a male who claims to be non-binary AND to identify as a woman at the same time, ie a non-binary binary person).
So what is one to do when one wants the transgender crossdresser under the trans umbrella but cannot exclude the cos-playing crossdresser without also excluding equally valid gender fluid trans people?
Solution: include the crossdresser under the trans umbrella. Solves all these problems.
Had a discussion about this with someone involved in the trans community for decades. Was throwing absolute hissy fits at me saying crossdressers were now included under the trans umbrella. Reasons much as that Twitter user - complete outrage that people who aren't really trans should a) be claiming membership of a marginalised group (transsexuals whose GD is so serious they do transition medically) and b) have their unacceptable boundary violations all the way up to crimes against females reflect badly on the old-fashioned type of transsexuals.
After posting a number of definitions, including the Stonewall ones, that person actually acknowledged that yes, trans activists have claimed crossdressers as trans, demanding acceptance of the position that as there is no right way to be trans, there's no real trans and there is no such thing as not trans enough.
Maybe we all have been educated too well by trans activists while this has passed that Tweeter by. But what they are completely missing in that long long thread is that they are proving our point: predators will make use of anything that allows them easier access to their victims. They will abuse self-id.
So either all of those male predators are accepted as trans as per the trans umbrella and evidence that identifying as trans does not render a male harmless to women OR they are accepted as predators using the trans umbrella to their own advantage. Either way, they're proving our point.