Don’t get me wrong, if you have a good jam or preserves it’s totally fine on a sandwich, and I wouldn’t turn my nose up at it. However, peanut butter doesn’t really need the help, and the extra sweetness from jelly is totally unnecessary. Toasted bread and peanut butter is all you need for a quality simple sandwich.
You are absolutely correct if that is what you prefer.
You are incorrect for me however, as I generally prefer mine with a little raspberry jam to shake up the flavor profile. Plain is good too however.
Can’t say I’ve ever gotten worked up over someone’s food preference.