Comcast did not slow down Netflix, please get this right!!!!!!!! They wouldn't allow Netflix to create a direct connection to their network, instead they wanted Netflix to use a tier 1 provider instead, which Comcast has agreements with for direct connection to their network. So Netflix wanted to create their own media network servers(CDN) inside the comcast network, but that would have been a conflict of interest as Comcast has it's own CDN service. That's when Netflix started complaining and crying foul and jumping on the net neutrality bandwagon. But this isn't really net neutrality, it's on the physical level, not throttling of specific packets. Net Neutrality laws have nothing to do with this, and would change nothing here.
It was later found out that COGENT, the tier 1 provider that Netflix uses to connect to Comcast was the one throttling Netflix, not Comcast!!!!!!!!!!!!!!!!!! They said they prioritize their retail bandwidth first, and wholesale bandwidth second. Again, I'm not sure if Net Neutrality applies here either, it might but it might now based on how it was done. They completely limited Netflix as a wholesale customer.