Yeshivas kick out students all the time, although in many cases its called “They are asked not to come back”, which is a nice way of saying get lost, we dont want you.
We are talking about students with behavioral issues or just some with learning issues. While things like Dyslexia are now more known and some yeshivas can handle it, sadly many cannot or will not.
Go to a NYC public school near a jewish area and see how many frum kids are in the special ed classes