Netflix isn't raising prices just for the hell of it. Prices get raised for two reasons: 1) Increased upstream costs (passed on to the customer), and/or 2) Increase in demand.
The reality is, Netflix has run the numbers and they believe that the demand for their product is such that most of their customer base will be willing to pay the higher price. They'll definitely have some attrition, but that loss in revenue will surely be replaced by the increase in revenue from the customers that stay. Believe me, they've already run these numbers.
Netflix has a great product, it is served through far more mechanisms than it used to be (phones, gaming consoles, televisions, set-top boxes). As demand has increased, I'm certain their delivery costs have increased. As Netflix's demand has increased, I'm sure the entertainment industry has raised their prices to meet the demand. It isn't that big of a deal. Okay, yes, they could have done a better job of publicly positioning the price alterations, but so what?
In the end, we have a company that raised the price of it's higher demand service and lowered the price of it's lower demand service. Is this really surprising?