Imagine you are looking for a How-To video on something very common but specific, such as changing a car part or Windows setting, and that when you search for this you are given dozens of options. All of these options are 20 to 30 minutes long and 90% of them are either inaccurate, out-dated, or automated click-bait. This lower 90% will have a disproportionate number of dislikes. Each time you click one of these videos the dislike ratio can save 20+ minutes of your life and this benefit is multiplied by dozens of videos and tens of thousands of viewers.
Not saying those other people are wrong mind you. Your lived experience is your lived experience and no one really has any standing to contradict that. Just expressing surprise at the degree of just how differently different people are reacting to this.
If you read the comments in detail you will see that people describe how they used the dislike count. It's therefore not useless.
It's not my intent here to comment on the utility of the feature in any universal sense - my comment is about the disparity between the reactions of different people. And it's just a casual observation, I'm not trying to argue for any thesis or anything here.