Once again, that section wasn't written for you, nor was it written to give people "permission" to play certain kinds of characters.
It was written to tell people who have felt marginalized or ostracized "Hey, you're welcome here, too. We acknowledge you and want you in the club." If you've never felt that way--either because you aren't part of that group or because you are but haven't experienced that marginalization, great! Nobody should have to. But for those who have, this sort of gesture can be genuinely meaningful.
Except that his response
is relevant to the question asked. It may be worded a bit snarky, but the core sentiment is that "No, I don't think it's impacted the inclusiveness, IME/IMO."
That's my experience, too. I've had gay players, characters, and NPCs in my games. I was the only guy in an otherwise all woman group, for a bit. We've had three couples in a game and other games where different "halves" of the couples played. I'd guess that my experience probably stems from the fact that I will (and have) walked from a group that behaves boorishly or boot a player of that sort from my game. The problem hasn't been in the games (mostly), but in the players. Bad behavior just stands out more in an already niche environment (see also: IT, executive retreats, sports, etc.).
I will say, as someone who initially strongly disliked the inclusion of said wording, that it hasn't been an issue. My opposition was because I don't think the topic has a place in the rules (pro or con). If the short blurb makes the game approachable to someone, great. I don't want sex/sexuality of any sort as a major feature in my D&D, though. That really breaks the "friendless orphan wanderers" mold that my group uses.

I say that a bit tongue-in-cheek, but it's true for most groups, IME. Narrating flirting (or more) with another guy, or a woman who's not my wife doesn't qualify as fun, even if I can separate reality from game. For even more icky awkwardness, my daughter joined our game, last winter.
The flip side to the short blurb being inviting to some folks is that it also gives other folks something to point at as "stupid" and bring the topic up "proactively", at their table, which could also alienate folks. Truthfully, those sorts of groups would alienate players no matter what, so it's a break-even for them. The point is that a little paragraph or two isn't going to suddenly make a table more "tolerant". It only exists for the few folks who are on the fence about whether something is OK -- strong feelings either way won't get changed.