This is what made it toxic.
Pick your battles.
Most haggling/negotiating being discussed here isn't about getting screwed with an unexpected fee, but about getting a better price before purchasing a service/item. This would be an unexpected fee if the driver didn't disclose this.
Those cabbies are working-class people usually. They often have families, and need the extra money. All they get is usually a few extra dollars; which means a lot to them, but very little to us middle-class people, who would suffer no repercussions financially.
One could see the running meter as a form of a 'tip' or 'donation' - not everything has to be seen in the context of "being taken advantage of", which makes it very hard to live.
This is very different from surprise fees from banks and institutions, for which I can see how a person might feel taken advantage of.
Those ones piss me off the most, in this way you are rewarding cabs who do this and kind of penalizing the ones that don't. In that moment, I am doing 180 and no way I am going to give that person even a penny more than necessary.