I think that advice for new players, that implies that there is nothing useful to be said about reconciling ideas and approaches and hence that the only recourse is to part ways, is bad advice.
There are well-known player-GM flashpoints in D&D play, that have been discussed and debated for decades now. Alignment, and fidelity to the divinities, are two of these.
The book proactively trying to structure things, and channel participants, down pathways that are likely to avoid rather than ignite these issues seems sensible to me.
I don't disagree with what you've said really. You could absolutely include additional advice, or reword what I had, to encourage more discussion. I have been very clear in my position, that I believe, with few exceptions, many of the problems cited in this thread and others are purely social. So more discussion is, in my opinion, always good.
For context, as people's opinions are based on their experiences. I've been pretty open about the fact that I DM, mostly, for randoms off the LFG subreddit, and play in my primary group where I only DM sometimes. I've done this for almost a decade. I have a 3-4 hour session 0 with these "random" players, a long form 1 on 1 discussion just about their character, and a discussion about what they want out of the campaign, all before playing a single session.
I believe my committment to proper communication is why out of what has to be hundreds of players, I've had to have an uncomfortable conversation with two. And out of over a dozen random DMs, I've never had an issue. Everyone else has, without exception, been a joy. I love this community, and implore anyone who is having a toxic or difficult experience with their group to look for better - because it's out there.
So whatever WotC has to do to both encourage communication and empower people to find a group that fits them, so be it. But as to the how best to do that, your guess is as good as mine.