This is about as basic as it gets.
OF COURSE children can pass CV-19 to others (like, their parents, grandparents, cousins, other children, etc).
The only ones who are pushing the “kids aren’t contagious..they really, REALLY aren’t” are the people pushing to open the economy back up pronto. Because, if the kids are home (to keep them from becoming infected at schools, which are basically a living petri dish of infection), parents can’t go back to work - at least not that easily.
I’ve yet to see a single credible scientific analysis from anyone that “proves” kids are not contagious. OF COURSE they are contagious. Just like they are with the flu, colds, and every other thing they come down with at school or elsewhere.
I have seen some articles that suggest that people that are asymptomatic (and which children might tend to be) do not transmit it as much. It could be as simple as they don’t cough and spew out so much.
And there’s also this article:
https://www.msn.com/en-gb/news/world/children-unlikely-to-transmit-coronavirus-says-study-cited-in-pms-push-to-reopen-schools/ar-BB13d37r