I think the problem with schools is that they have an access status that actually falls between access=customers and access=private. The trouble is that access=customers generally implies a fairly permissive access.

The reason for not normally mapping access=private toilets is that amount of noise they would add to the map and the risk that data consumers would fail to detect that they are private. That also applies to cafe and restaurant toilets, which may be access=customers by law, but should be findable without a map by those close enough to use them and allowed to use them.

I would actually suggest that school toilets are no different from many other features that might get mapped within a school.

I’d also suggest that there are other places where it might be appropriate to map private ones, because the building is actually available for public hire (as in fact are most schools).

I’d certainly suggest that changesets deleting these should be challenged, and possibly escalated to the Data Working Group.

Most rules in OSM should be subject to common sense.

Actually, school toilets generally have additional access restrictions on toilets. Some will be staff only and some children only.