I get that the meteoric rise in online video streaming by customers puts pressure on ISPs because if affects the oversubsribe ratio that they can use (which is required to turn a profit) while still providing a good user experience.
But what I don't get is why you can possibly blame Netflix. Your customer requested 100GB from Netflix last month. Netflix supplied it based on your customer's request. If you think 100GB (or however much) data in one month is too much then throttle your customer, but do it fairly based on each customer's usage and don't play favorites with which companies you allow your customers access to. 100GB of Netflix traffic should be treated the same as 100GB of porn, or whatever else your customer is getting up to.
My university's residential internet connection started undergoing major strain several years ago, primarily due to online video. So they implemented traffic throttling. I don't remember the precise details, but it was along the lines of a daily 1GB of unthrottled data between 4PM-1AM after which speed was reduced , and no throttling from 1AM-4PM. This was a completely fair and balanced way of providing a pretty good user experience while limiting traffic during peak hours to avoid congesting the network.