Treating each other with respect also means that you should give your classmates the benfit of the doubt, and interpret what they say charitably. If what they've said sounds utterly stupid to you, try to determine why they believe it. If so, help them figure out what it is. You should listen to each other's opinions with respect, but you should also subject them to scrutiny and criticism. We expect you to defend your claims with arguments, so you are perfectly entitled to require others to defend their claims, too.
Conflict is inevitable in a philosophical discussion.
You're not all going to agree on the issues. Remember that when others disagree with an opinion you've expressed, or when they criticize your reasons for holding that opinion, they're not attacking or insulting you. All of us hold false beliefs. The whole point of philosophical discussion is to try to find out which beliefs these are. We can't do that unless we subject our beliefs to this kind of criticism.