You are correct: cordial discussions are allowed; mud fights are not.
Cool!
Your selection of the term "Cordial Discussion" is interesting. Search older threads in the religion forum / smokey back room for that phrase and you will find the term too has a history.
For example:
http://www.freerepublic.com/focus/f-religion/751519/posts Note the ground rules heading the thread. Interesting bit of our historical past.