You are defending your own opinion, just not in a way that offends your opponent.
What happens when you disrespect someone, or offend someone? What do they do? They try as equally hard to disrespect or offend you, which causes you to try equally as hard... and so on and so forth.
The problem with arguing is that people's objective changes in the midst of arguing, it's no longer about getting your point across, it merely becomes about "winning."
However, by acknowledging your opponent's view you aren't being submissive in yours, you're simply acknowledging the fact that another view exists, then they'll reciprocate.
How about a more relatable example for ya
Feminist argument: "Macho-ism is so stupid, and degrading to women! We had to fight and protest for the right's that you men were naturally given! I'm so repulsed by how male chauvinistic pigs continue to treat us women like objects instead of equals! After all... (her argument continues)."
Me: "I can totally see why you would feel that way, and if you'd listen for a minute and allow me to explain my side, you might get a new perspective on things. (then continue to your view)"
An argument is no different than another no matter where it takes place.
-Richard