I second what BeanieTeen says about NOD.
Re gaslighting, it is very common. Advertisers use it, politicians use it. It's common (still not ok though IMO) BUT it's not a serious threat to anybody because we all know the truth really. And we can talk about it and call them out. There's an existing public discourse about it to the point nobody really expects politicians to be honest!
It's also completely different to have a person gaslight you once or twice than to have your world narrowed down by a gaslighting abuser who basically undermines everything you think, feel and experience - perpetually,. Someone who isolated you, so your only source of info/confirmation is from them. To get to a point where you're so brainwashed - because that's what gaslighting does in part - that you can no longer trust anything you think, feel or perceive. That is totally different. Even having a chronic gaslighter as a friend and she gaslights you all the time, the fact you're not in an intimate relationship with her dilutes the impact somewhat. Being gaslit by people less close can be annoying and even upsetting, it can hurt, but it's not damaging in the same way as an intimate partner relationship.
And just like everything else related to mental health, it's picked up by social media users who confusingly to me, love to have any label at all that can make them appear to be a victim. Some definitely have experience(d) whatever label they're throwing around/professing to be an expert on. But the majority are just desperate to be part of an algorithm.
I'd compare it to people who have had a bit of a bad day at work, got rained on on the way home then saying "I'm so depressed". You had a bad day, I've got sympathy for that, but it' not the same thing as depression.