I guess the difference was (is) that we had a natural immune system when I was a kid. We played outside, we got dirt into our cuts, we put weird stuff into our mouths and we ate real food.
Today kids grow up in an almost sterile environment. They're poisoned with vaccines from their first days then again when they get into school. They eat industrial food and in general, their body defence is almost non-existent. Then parents are told that they need more vax, that their kid has a rare illness and everyone wonders... why?