Everyone has an opinion about everything. That's not so much a problem. The problem is that we LABEL our commitments as opinions. That's very much a problem. What the heck is an opinion?
Let's step back from the concept of opinion and start with the more basic furniture of the human mind. We clearly have beliefs. Beliefs are things that we think are true. I think that my computer is on, that it's wrong to cheat on your taxes, that it's 2020, that God exists, and that 2+2=4. Those are all things that I think are true. They are best characterized as beliefs.
In addition to beliefs, we have desires or preferences. I want the US to pivot towards green energy, I prefer dark chocolate to white chocolate (is that even chocolate?), and I I enjoy seafood. None of these are things that I think--that would misdescribe my mental situation badly. They are things that I want or desire or prefer.
Beliefs and wants vary in a number of different ways. But the most important, according to philosophers, is their direction of fit. We want our beliefs to conform to the world. That is, we want our beliefs to be an accurate representation of the way the world is (in most cases--there are interesting exceptions, but that's a digression for a fake news post). When the world changes, our goal is to update our beliefs to reflect this fact. On the other hand, we want the world to conform to our desires. If we want vanilla, we don't give up this want upon seeing that only chocolate is available. We go somewhere else to get vanilla. We wrap the world around our desires. So beliefs and wants have different directions of fit when it comes to their relationship with the world.
What does all of this have to do with the concept of an opinion? Just this: the concept of an opinion is ambiguous between beliefs and desires and this ambiguity causes us trouble. Sometimes we express our beliefs as opinions. For example, you might say, "In my opinion, solar power is cheaper than hydroelectric power." Other times we express our wants or preferences as opinions. For example, you might say, "In my opinion, chocolate is better than vanilla." When we use the same concept to describe both, that's a recipe for trouble.
That's because beliefs can be properly criticized when they are out of sync with reasons. Desires and preferences cannot. If your friend prefers broccoli over brussel sprouts, OK. Nothing for you to say about that. There's nothing for her to be right or wrong about in a case like this. But if your friend believes that guns cause more deaths in the US each year than stairs, there's quite a lot for you to say about that. She has a belief, and it either matches up with the evidence or it doesn't. Where it's strange to criticize a friend's preferences, it makes total sense to critique her beliefs.
So by using the concept of an 'opinion', we mask the true nature of our commitments. Some are are properly criticizable by appeal to reason, and some aren't. But the use of 'opinion' to describe both papers-over an important distinction that leaves us all the more confused.
Here's a more sensible suggestion. Label the things we think as 'beliefs'. Label the things we want as 'preferences'. Be clear about both, and ask people to be clear about their reasons for the former (but not the latter). Relegate 'opinion' to the rubbish bin.