I believe that, in the specific case of "alternative sexualities", there's a relatively new global consensus (being pushed on or not, I'm not big in tinfoil hat theories although I believe there's an agenda behind it) that classifies people outside of the heterosexual norm as "special" and "worth of praise" for their bravery of coming out and deciding to announce the world they're not like the biologic norm. Even when the fact doesn't require an extensive effort from the person in question or, according to themselves, not even a choice, the world rejoice on their newfound alternative lifestyle.
Now, going back to the point of it all. We humans are tied by our humanity, that's a fact. Human nature is to defy limits whereas those are personal, as a group, as a society or civilization, pushing boundaries and not conforming is part of our DNA (the reason why certain political ideologies will always fail but that's another thread) and we like to break those boundaries at every step: In our jobs, in our life, in newfound scientific discoveries, inventions, being the toughest there is, being the most apt, fit, smart, etc. As a group or as individuals to the point we get depressed when we don't reach any of that, any kind of goal related to being "special".
And that's when these celebrations come into play. We know being gay, a furry, bisexual, trans or whatever thing... is not really something special. Everyone says they were "born this way" but in a society that is inherently competitive and where is tough to "get attention" from a sea of other special snowflakes, we created this showcase for individuals that otherwise would fail to be noticed in any other way.
The words "bravery", "inclusion", "visibility", "validity" are all just empty words. What they want is their 15 mins of fame (or day, or month), as a group, as individuals or as a collective. And with the advent of social media and hyper-connectivity, these showcases became power struggles. They became platforms to boost an individual's power over other people because we, collectively, agreed on giving them attention. Even this forum, even this post is a form of attention (like the old saying; 'there is no bad publicity, just publicity'). They need a platform, they need followers and they need enemies in order to succeed in seizing power for themselves. And here we are.
We collectively created a monster where people is measured by their popularity, their gender, religion and race instead of their achievements, feats or prowess. Internet and being hooked on info 24/7 accelerated the process and corporations doing their part for profit cemented the issue.
So, going back to the premise, what's the point? Power. To accumulate and execute power over the opinion and will of the masses. Simple as.
