I think that in general your second thought is correct - it's mainly an inclusivity event.
Libraries are an interesting sector. On the one hand they have a history for a good many years of being very significantly dedicated to political neutrality and free speech. And to their credit, for the most part when activists have directly challenged them on those grounds, around things like removing books, they have stood their ground.
On the other hand, they have tried to reshape themselves a little to seem more responsive to the community and as a kind of community hub. To that end there tends to be a lot of thought about how to welcome everyone and serve their needs. And then you can add to that something that isn't always well known, most librarians now are on the political left, and many of the national library organizations are very strongly political, enough so that it's become a contentious issue in some cases, the American national library association for example.
As a result, when they are thinking about inclusion, they are often now thinking about it through the lens of identity politics, EDI, etc. Because that is the lens many of the librarians in charge have, and quite a lot of them don't actually realize the extent to which that is a political lens.
In addition, many are getting their goals handed down from the political level. So for example, where I live there was a set of priorities from the government which centered on minority ethnic populations. In one library system the board and head library, who tend to be very woke, took this to mean that as much as possible all programming should reflect this as well as book aquisions.
So you have these people trying to figure out, how do they squeeze queer issues into children's programming? What about that is fun and relatable to kids? Well, probably nothing, really, but they are determined to get it in there one way or another.