Rsv and croup are not more contagious than Covid though.
They are about as contagious, and both more dangerous to children.
but it's not a novel virus and therefore doesn't spread the same way.
Okay, look, I will try to explain this carefully.
Novel viruses spread fast through a population because nobody has immunity to them. Whether they're 'new' or not is not the point, whether they're new to that population is the point. So measles wasn't a novel virus in the 17th century, but it killed lots and lots of native Americans because to that population, they'd had no exposure to it, so it was brand new.
To young children, every disease is new. That's why viruses go around like wildfire at nurseries - the population of under-3s don't have immunity yet, because that virus is totally new to them.
By the time children get to school, most of them won't have to worry about RSV. The reason for that is that most of them will have already had it, before the age of 2. That's how contagious it is - it infects almost every single child in the country in their first two years of life.
It's no wonder you're angry and confused about the restrictions though because you clearly don't grasp the basics of the situation.
I'm trying to stay polite here, because these are important issues and I don't think slinging mud helps.