It just seems like playing to the "everything goes" crowd that invents gender identities to be special
What do you mean "playing to"? Is it impossible for you to understand that the vast majority of the LGBT comunity is attentive to the genderfluid view?
Are your internet-fueled misconceptions about what that really means to people who really live in that condition or aspire to understand them so absurd that you can't accept reality?
And when it comes to why blame Tumblr,
Why do people mark a ridiculously off topic social event to paint the picture of a whole ideology?
This screenshot is more about the quest of a (probably young) person trough their own question of gender and sex than about the whole conjecture of the genderfluid question.
I bet that would sound strange for them, because that's where they get their information and socialisation from.
But outside the internet, outside of schools, outside of colleges, outside of jobs there are a plethora of amazingly different people, capable people, brilliant people, common people, that deal with their own questions about gender fluidity on a completely different way than of that sub-niche of the Tumblr community on the Internet.
And yet, my point is, why the fuck would they care about that young person and their blog? In which form this can justify socially voicing your DISLIKE to the LGBT community because they simply are not against view as you are?
Where does the this facade narrative of justification for homophobia really ends?
This is what homophobia looks like today.