Are you disrespectful if you didn't agree to someone's opinion?

Since it’s election year over here people are madly defensive about which political party they’re for. A friend like to keep posting that she’s for a certain politic party and when someone told her that “it” is not for that political party then the friend flipped on her for being disrespectful because “it” didn’t agreed with her.

So is it disrespectful if someone don’t agree with your opinion? I think not but others thinks so.