While your statement of "of course they are not happy with it" is true, it's not a defense in my mind. The same could be said about any regulation that controls indefensible practices of companies.
From oil companies, to fishing companies, to waste disposal to whatever, most companies from a purely technical viewpoint would be more than happy to get rid of regulations that control what and how they can do business. Yet, we have those regulations in place for a reason.
In this case we simply ask that ISPs deliver the bits we paid for. I don't want Comcast treating my bits differently anymore than I want my mail carrier to hold my packages ransom because they seem important and I'd probably pay more for them.
My mail carrier doesn't read my mail. Comcast shouldn't either.
Yes of course it always depends on which side are one on. If I'm the customer sure I don't want isp throttle my bits but If I'm the isp, I want the freedom to throttle.
Net neutrality requires that ISPs actually deliver what they've advertised and collected payment for and claimed to deliver. Of course they're not happy with that. It's much easier to deliver less than promised but still pocket the full payment.
Correction - make it comply with Title 2. Net neutrality isn't what the FCC killed, Title 2 (which is still a massive blob of legislation, even if you discount the stuff in forbearance) is a set of laws that ensure a kind of neutrality.
All the work to make sure it comply with net neutrality.