A. The rule isn't that packets must be delivered at the same time, the rule is that you can't shape based on source (but you CAN shape based on other things - so, you can prioritize VoIP for example).
Basically it means the telecoms can't favor their own streaming services over Netflix.
B. The clients are literally paying the telecoms in order to get access to Netflix. That's what they use their internet connection for, that's what they pay the monthly bill for. Why shouldn't they be able to stream?
I don't know about the specific rules in the US. But in Eurpean hacker circles when talking about net neutrality the strong definition is used. Meaning the provider should not be allowed to change quality at all.
Some think it would be fine as long as the user indicates the quality level he wants, others are against it completely.
There have been a number of debates of the years, at the Chaos Communication Congress for example.
In the US, under the OIO/Title II, an ISP could do basic network management (e.g. blocking ddos attacks, holding people to the bandwidth limits they paid for) and basic QoS, though I'm not exactly sure how that was defined or implemented.
Because objectively there is a limit on bandwidth that grows slower than streaming business and it is unfairly distributed among users in general. You can think of 10 items or less as an analogy. If I try to use my LTE from 17:00 to ~19:30, my bandwidth is almost dead because everyone returned from work to watch their feed. The only way to return my fairness is to storm the network with millions of torrent packets or video read-aheads. If ISPs would sorry me and charge less (I get exactly the same bill, btw), then it is equivalent for them to simply charge heavy users more or throttle them down.
Edit: it is worth noting that ISPs hugely oversell their bandwidth.
