I think that highlight my main gripe about what I'd call excessive inclusion. Sure there are some people who identify as male, who will go on to become pregnant, but they have to understand that they are not representative of anything. The number of trans-men who also become pregnant is so tiny that it's beyond an edge case, it's not something that needs to be accounted for everywhere. That's not to say that they shouldn't have the same rights as everyone else, or that we should tolerate actions taken against them. It's just that some groups are so tiny that having special language or accommodation for them makes little sense.
If they are successful in have a pregnant trans-woman in Unicode, you just know that, depending on the depiction, it will be used as "The fat guy"-icon.
Personally I use it for "I ate too much" too. Half the fun of emojis is the new unofficial uses that evolve (I wonder what the fruit peach folks' thoughts are).
I don't see the problem of including small groups - they are the ones who are most invisible and marginalized and therefore in need of recognition. You say it makes little sense, but to me it not only makes sense but is self-evident. Even if you're right, I can scroll through my emoji map and see many that are even more niche, yet none of them receive the angry flak GNC emoji do. (Not to even mention the even more obscure items in the rest of Unicode.)
Can we not use the word car because motorcycles only have two wheels? Why do we need to change language for a few hundred people worldwide? Why do trans men get pregnant since it is the least masculine thing possible?