Opinions are opinions. They should be stated and treated as such. If your "opinion" is stated in the form "x is y," then maybe you are the one who should be more conscious of the way people communicate. Sure, it's just an opinion; that's fine. Just don't expect anyone else to take it as a fact or agree that it's at all meaningful outside of your own head.
I don't agree with this assessment of the problem. Some people want to participate in discussions about how things are or how things work or why things were done or what actually happened -- discussions of fact and logic -- yet they want to inject anecdotes, generalizations, metaphors, analogies, and other abstractions.
It's irritating and intellectually backwards. But it's not going to stop, because most people less interested in what a discussion is about than they are about making sure people pay attention to their contribution, whether it's valuable, on topic, or other.