Agreed. I do too. Heck, the primary reason I took up DMing is because of my experiences as a player.
But, I've had quite a large number of really, really bad DM's. I probably was one of them. I'm a fair DM now, although hardly a great one. Most of the reason I'm not a bad DM anymore is that I was willing to learn from my mistakes. And, as such, when I see others promoting exactly the same stuff that led to train wrecks in games I'd either run or played in, I don't think it's too unreasonable to chime in with a, "Well, in my experience, doing X is going to lead to a bad thing."
But, there is still a LOT of advice thrown around that amounts to, "Well, you're in the big daddy chair, so, if those peasant players aren't happy, they can leave".
Not exactly the most productive of advice.