It’s kinda sorta true, but not really.
Overrated just means “rated higher than you think it is”. It doesn’t exclusively mean “it’s popular and I don’t like it”. It doesn’t even have to be popular, it can just be critically acclaimed. It also doesn’t mean “I hate this”, as you’re also able to say something is overrated and still like it. You’ll also be surprised at how many popular things are also not critically acclaimed. So is it really overrated if critics think it’s mediocre or worse?
For example, you find a show, watched it and enjoyed it. You think it’s a solid 7/10. Pretty good, you may or may not watch again. Then you find out that it’s ridiculously popular and everyone you know and the press says it’s a perfect 10/10. Really? You enjoyed it but not that much.
That’s a great example of you thinking something is overrated.
I feel like most people throw it on something they hate because they feel it adds a seal of authenticity and rebelliousness to it. They’re not being a sheep like everyone else is. Why can’t you just say you think it just sucks?