At least in my wholly un-researched, personal opinion: No, I don't think this policy is attracting new players. The word "attracting" indicates, to me, that the presence of this thing is not just a contributing factor for someone choosing to play, but is in fact what gets them to even consider playing in the first place--that, without the "attractor," the person in question would not even have stopped to think about D&D whatsoever, let alone the specific question "Do I want to play this?"
Advertising is a thing that attracts new players. Hosting organized play is a thing that can attract new players. Disseminating information about one's products is a thing that can attract new players. Individual proponents--such as DMs--who intentionally go out and try to find people who didn't play, but who would be happy about something in the books, can attract new players.
Including a particular line of text in the book does not and cannot, in and of itself, "attract" new players. It can motivate people who are already looking at the game to try it; it can motivate people *already* playing to keep playing; it can inspire some current players to choose to attract other people who don't play. But the mere presence or absence of particular text does not, in itself, make non-players into players.
My problem is that "attracting" feels too much like an action, and written text by itself cannot act. It can passively encourage action on the part of others, but it cannot act of itself. With all of that said, it may be that I am simply taking the question at face value, when it was meant to be sound-byte-y and interpreted in a lax way. E.g., "Does this contribute to more people choosing to play D&D?" To which my answer is a firm "maybe." Other games have been supportive of things like gender stuff for a long time already, so among people who already play TTRPGs, I don't feel like this is enough of a "splash" to make a particularly meaningful difference. Furthermore, although it's unfortunate, we have to remember that changes like this can also drive closed-minded people away. Such people will be uncommon, to be sure, but I'm not sure that they are negligible compared to the number that will decide to stick around primarily/specifically because of this particular text.
And all of the above should be considered sharply distinct from whether it is good that we have this text, and the overall slow changes in D&D that this bit of text is just one example of. I know some people--perhaps not very many, but some nonetheless--use games, particularly RPGs, as a way to "safely" explore their thoughts and feelings on tough questions because there's a natural "silo" built into playing a game. While I sincerely doubt that such people will decide to start playing D&D because of this text, people who already play D&D may feel encouraged to ask questions of themselves and think about their lives, which generally sounds like a pretty good thing to me.