No, it isn't what bumpers are for.
Yes it is soupdragon, or do you think they're just for show?
I'm very good at parallel parking but sometimes spaces can be tight and I will squeeze into a spot and nudge cars gently with my bumpers because that is what they're for.
Bumpers are very robust at infinitesimal speeds. That is what they're there for, apart from other more high speed collisions.
I drive very nice cars but that's not the point. If I was worried about them getting damaged, I wouldn't take them out; I'd just look at them in my hermetically-sealed underground garage. If I drove something with self coloured bumpers or a vintage one with shiny chrome ones I'd have to put up with the inevitable damage.
I leave my car in its space and hope to come back to find it undamaged. If it's damaged then I'd swear but that is what insurance is for.
I fully expect people to bump the front or back of my car gently without causing damage. Believe me, it can be done though I would cringe if I saw them doing it.
I'd rather not park close to someone with a tow-bar but I can't stop them parking next to me when I've gone.
If they want to rely on parking sensors that's great too but I wonder about people who routinely rely on sensors or sat nav rather than eye and judgement.
Parking alongside people in a car park is different. Of course you don't crash your doors into their car as you're getting out. Though lots of cars have protective bumpers running along the sides. That's a good idea and I imagine that's what they're there for rather than just being for show.