It isn't the power to protect YOU from yourself that is the issue but the power to prevent YOUR presence in dangerous situations making them more dangerous to OTHERS by hampering the police and fire authorities. Your power to do only what YOU want at any time is limited.
Federal involvement comes when State authorities request help and it has resources which the States do not have.
OUR Constitution states the purpose of the government it created as "...to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity...." That is good enough for me.
I wonder how many idiots (many I'm sure) were actually WAITING for the mayor to tell them to leave, then couldn't.