Opinions are all very well but are based an a personal expectation, understanding or preference. If they were to be supported by some practical evidence or demonstration they would no longer be opinions. If not supported opinions aren't any more valid than belief in a personal god, or indeed God. Thoughts anyone?
I think most people, when questioned, will try to give you evidence for their opinions or at least their values.
Opinions CAN be supported by evidence, often they are, but they are still opinions. Pew Research just published a piece about how people have trouble distinguishing between facts and opinions, especially if they don’t agree with it. [pewresearch.org]