I think you're both essentially right. Yes, you can lose weight eating twinkies. If you are taking in less calories then you burn, you will lose weight. But figuring out those two numbers is pretty complicated. And, as the Times put it -

That humans or any other organism will lose weight if starved sufficiently has never been news. The trick, if such a thing exists, is finding a way to do it without hunger so weight loss can be sustained indefinitely.

That's where modern diets like paleo and keto come in. If you can sustain them, they can be a great tool for weight loss, because reducing sugar reduces insulin spikes and helps control hunger. Most people can't sustain them though. Reddit exacerbates this problem, because people who are currently on the diet are the only ones active in those subs, and those who drop out aren't included in those perspectives. So the discussion is entirely driven by people who are on these diets, most of them who will only last a few weeks to a month.

The answer for most I believe is somewhere in the middle. If you cut all carbs for a month it won't do you much good long term. But if you structure your meals with less carbs and more food that helps with satiety, you'll see lasting health benefits.