People who have an opinion on everything are usually pretty easily dismantled by someone who actually knows a given topic well. But there are also loosely and tightly held opinions. Smart people know the difference. I have lots of surface level opinions because I can't deeply know everything. But I recognize this and hold such opinions loosely. Just enough to get by. Or I just don't form an opinion if I don't need to. I dont need to have an opinion on everything and couldn't have meaningful opinions on everything even if I wanted to.