Why is there a Muslim and Islamic holiday on the US calendar?

This is absolutely ridiculous! Why in the hell is there an Islamic Muslim holiday recognized on the US holidays calendar? This needs to be removed and any other non-US non-American holidays should not be recognized on the US calendar for holiday. I’m not saying that people can’t celebrate their own stuff but why is this being recognized on the US calendar? That’s not an American holiday people are free to do whatever they want and practice whatever religion they want but why is it being forced down Americans throats.