It's reductive but important, because it's not easy to tell who actually knows what they're talking about and who talks out of their ass. It's better to assume nothing you read is "right" than try and guess what 1% is "right" yourself.
In general there are "some" people with real experience, but they don't usually stay long. For example, a doctor who tries correcting bad circlejerk medical advice but gets downvoted and called a liar and a fake is only going to try correcting the bad info so many times before giving up and either staying silent, or going to a website where people actually think to talk.
It's not that "every" opinion is baseless, but if there's 99 lies and 1 truth, and you can't tell which one the truth is, you're better off treating them all as baseless because guessing will usually lead you to the wrong answer. This website has way too many kids and NEETs larping as professionals of every topic, it's not enough to trust anyone who says they're a real lawyer or doctor or expert.