Personally - I often give more credit to an opinion that at least recognises that it is an opinion, than one dressed up as statement of fact.
But yeah, what you have noticed is a social phenomenon that seems to be embedded in our society ie "I believe it, so its a fact
to me" (the 'to me' is implied unconsciously). I think this has arisen since we educators began emphasising the teaching of students to voice their opinion on topics they don't know much about, over spending time building solid valid arguments based on evidence and the like.
Obviously I'm not talking about all students in all places, but I do have what I think is some basis for this opinion... I have worked in teaching Logic and Argument to 4th year Education students, I've marked hundreds of essays written by people about to become teachers, and to be honest, only a small fraction seem to be able to grasp that there can be a big difference between stating an opinion and making a valid argument, neither of which necessarily establishes 'facts'.
Facts are slippery little suckers.

J