Death caps aren't red, they're more like a pale green or even entirely white. You're probably thinking of fly agaric, which is also poisonous but not nearly as much so as death cap.

There is a wide variety of poisonous fungi and some of them can look deceptively similar to edible ones. "All poisonous mushrooms look similar" is really not true so yes, never eat anything that you can't identify with 100% certainty.

Death caps actually don't look obvious at all.

https://en.m.wikipedia.org/wiki/Amanita_phalloides

Can easily be mistaken as edible.

Edit: just clarifying, I agree with everything else you said.