I don’t think there is any more to this. But I also don’t think it was ‘teacher told kids Santa doesn’t exist’.
Lesson was about saints, children asked about St Nicholas, teacher explained St Nicholas, children came to the logical conclusion, parents devo (I mean, I sort of get it but also it is what it is).
I just don’t think the teachers did anything wrong here, but it made a click bait news story when the school responded with a blanket ‘we will pass this on as a learning opportunity’, just to shut the parents up.