It’s a sticky wicket.
Current internet service providers never promise that you will get content from any source on the internet as fast as the slower of your own link to the provider or the provider’s own link to the backbone. To be able to keep such a promise if the providers were forced to make it universal, they would need to make investment in equipment bandwidth that most customers would not use or would only use rarely. This would jack the price way up. I would be more in favor of full disclosure to customers of individual ISP policies on the matter. If Joe Blow Telecom is slowing down a competing feed from Jim Schmoe Telecom, Joe should be required to say so to potential and current customers. Then Tim Grow Telecom could advertise that they slow down nobody’s feed, but they also charge more for that characteristic. And customers can choose what they want.
I have to admit that I am out of my element but I think an example of what I mean is when all Canadian ISPs purposefully slow traffic to/from P2P sites.
If the bandwidth is the same why should ISPs be allowed to slow or block you from accessing sites they don't like?