Saying that commoners are equal to nobles? Totally ridiculous and a sign of insanity.
Saying that they should be treated kindly? Perfectly valid and at worst a sign of eccentricity.
If your adventurer is getting picked on by one noble, then make yourself valuable to a more powerful noble. Perhaps you may still be a dog, but only a fool lets someone else beat up their prize hunting dog without good reason.
what I was trying to say, thanks