Why do people dislike Nexon?

Yes really. People paid for the service, and they deserve to keep that service. Not honoring the fact that a service was paid for is no less than a scam.

Elemental weapon bonuses are not a service. Gachapon is a service. It lets you trade NX cash for in-game items. Elemental weapons are just in-game items with properties that they are free to modify. Even if you directly traded cash for the items, they should still be subject to balancing. Immutable items just makes balancing more awkward to achieve.

You always piss someone off by nerfing something they like, so it's not something you want to do too often, but to call the removal of the boosts a scam is a joke.