I'm going to rat out a classmate for cheating on nearly every test
Why are you turning on your classmate now?
I think that academic cheating is immoral and I don't want to be associated with people who cheat their way through life.
It's frustrating to see someone win by cheating, especially if they are doing it continually. If you do report them, do so in a quiet manner. Some schools offer anonymous reporting.
I'm going to call them out in class and ruin their reputation
I think that you should do it in private so that you can not embarrass them. I do think that you are doing the right thing though, it is not okay for anyone to cheat on a test.