Is my principle really allowed to send me home and then make my absence unexcused?

I go to a public school in the Parkway District. I got in an argument with a teacher and I said something bad to that teacher. (I know of at least 2 other students who have said the same thing to that teacher. One person said it the day after I was suspended and nothing happened to them. The other student says that to the teacher all the time and she has admitted to saying it.) I was then suspended for the next two days and my principle sent me home that day. The rest of that day was marked unexcused because that wasn’t part of my suspension. My principle said that it’s unexcused because I wasn’t there and didn’t have an excused reason why, even though she sent me home because she said she didn’t want me in the school environment for the rest of the day.