Well, I am gay and well before puberty or any pronounced sexual awakening, I was aware of some “gay” tendencies. Even more significant, I recall having “childhood crushes” (probably somewhere around the age of 7) and they were NOT for girls. So, how do you respond to that? There are many many other anecdotal stories from other gay people with similar stories (and some I know who are are “closeted” and have no interest or political agenda (as you suggest) for making such assertions.
Also, the picture you posted may not be real. On many social media sites there are pictures an GIFs with captions saying just about anything, so I wouldn’t let something like that be the impetus for your “irritation.”
Also, there was some discussion above…sexual orientation and gender identity are absolutely different but there is no need for me to post a wall of text regarding the differences when you can simply google it and research it for yourself, if it is of interest.