[PoignardAzur]

From what I remember, the crux of the matter was that the change of regulation would give more negotiating power to ISPs when it came to common infrastructures they shared with large cloud providers (Google and co).

The status quo was highly advantageous to said cloud providers, which is why they lobbied so hard against net neutrality changes. And since people on the internet get really vocal about perceived threats to the internet, the lobbying went viral.