Turf wars
So FCC vs FTC. Plus lobbying. The whole telecommunications vs information service issue has long been a problem, or solution for lobbying. Which includes lobbying by the agencies because if they get to regulate, then they can grow empires. Or because of the $$$ involved, lawyers and lobbyists get to bill big.
To my simple mind, it should be a 'communications service'. Define endpoints, ie user to server, user to user etc and then the plumbing that joins them. Then apply regulations to communications, and job done. Except doing that enjoins parties that don't want to be regulated this way. So currently it's been ISPs vs content providers and attempts to regulate just the ISPs activities, and the FCC's baby. Regulating the whole flow would mean content providers would also be expected to behave neutrally, ie can't favour or prioritise some traffic over others. It could also mean FTC/FCC becoming the arbiter in peering or connectiivity disputes, ie traffic dropping due to disputes around interconnect costs, which neither side probably wants. Or would do the usual thing of lobbying and finessing any regulations or rulings in their favour.
From a user POV, it would make more sense. Users don't care who in the chain is causing the bottleneck, they just want it to work.
Biting the hand that feeds IT
