This is a common motte & bailey argument. If you press in on "are all foods really the same?", you get "Oh, no, of course there are differences", but as soon as

This is a common motte & bailey argument. If you press in on "are all foods really the same?", you get "Oh, no, of course there are differences", but as soon as you're not pressing we end up right back at "you just have to cut your calories because all calories are exactly the same and it doesn't matter where they come from". Ironically, you demonstrate this in your last paragraph. If all calories are the same, yeah, just cut 100 out some other way. But if they have different effects on hormones, satiety, any number of other systems, then it may not be "simpler and more effective" to "just" drop 100 calories as a snack. You may need to actually change what you eat.