I'm sorry obese people but you are obese because you consume too many calories. Lots of reasons why! but ultimately that's the truth of the matter
That's a vast oversimplification which doesn't help anyone.
I've said elsewhere, I've gained dramatic amounts of weight three times in my life - one in my mid teens, once in my mid twenties, and once in my early thirties. I've lost it each time, but every time the reasons for gaining weight were different and the weight loss methods differed too. And there are healthy and unhealthy ways to lose weight too.
You need to understand why you're overeating, what you're doing wrong and come up with a sustainable life plan to change the bad habits and replace them with good ones. And those need to be realistic. I mean, cooking from scratch so I can see what is going into my food works well for me because I like cooking and am interested in nice food and good flavours. It's been relatively painless. One of my best friends hates cooking and finds it stressful so it wouldn't work for her.
I've always been slim because I've watched what I eat
This may also be true for you, but I've seen some fairly interesting studies suggesting that slim people start off with a preference for different flavours and textures and food which make it easier to stay slim. Dunno how accurate these are, but I think you're making it sound easier than it is.