And you may, or may not, also be as stupid as your opinion. But, philosophically, I respect your right to have a stupid opinion, and I will show you as much respect and courtesy as you deserve, depending on if you behave like an asshole, or not.
See, you are not your opinion, and I - apparently unlike many people - do actually have the mental faculties to keep all these things separate.
Conversely, I expect that my right to an opinion will be respected, even if the opinion is not. I expect a level of courtesy due to me as a human being, and will judge both your intelligence and character by your ability to separate them.
It's fine to call me a bitch when I behave like a bitch, but calling me a bitch simply because you think little of the sentences I have uttered reflects badly on you, not on me.
This is both philosphical and semantic. Many trolls will trap people into crossing the line between shooting down an opinion, and shooting at the person expressing it.
Similarly, many people - foolishly - confuse attacks on their opinions with attacks on themselves. It is a poor idiot indeed who cannot understand that opinions are like underwear, to be worn, displayed or hidden, then discarded when they no longer have value.
It is a component of class warfare to convince people that opinion and self are the same. If they are the same, I am weak if I ever change my opinion, while strong by remaining stubborn. To attack my opinion, then, is to attack me, and I must defend myself. Therefore conversation is destroyed, communication breaks down, and the muddled masses are more easily controlled.