Most can still afford a dummy, and ones who can't often just let the baby suck on the mothers finger (much like the nurse in SCBU did for my baby)
And we've also got lots of things that people living in poverty can't afford, like more than just a basic crib or even just a box or drawer, bottle warmers, disposable nappies, blenders for weaning/baby puree, all sorts really... that doesn't mean we should all get rid of them or that they're not very useful.
I get that lots of people love to judge other parents. Parents are often worse for it for some reason. But the dummy thing has always been one of the silliest to me, from years before I even thought I'd have children. It's a dummy. It's a bit of plastic. There are much more worthwhile things to "hate seeing" a parent do, especially when it's just to comfort their baby. I guarantee you, whatever choices you make with raising your child, there will be a bunch of people judging you, literally anything you do... so don't complain about it too much when you overhear it, because you are judging others on something so trivial. And thinking you sound perfect when doing it! And trust me, nobody needs to fight for people who don't want to use a dummy, because it's something that's so often talked about already. Often wjen trying to make other parents see how "wrong" they are for using one.
Seriously, unless somebody is actually harming their baby, you should just keep comments like this to yourself. You obviously haven't got it right yet, so are in no place to be saying what others should or shouldn't be doing because of how much you hate something. And honestly, yes, sometimes all a baby wants is a bit of comfort, not always just to be fed or changed, just like adults really, so if people want to let their baby have that comfort they're craving, I'm not seeing the issue?