More than likely Verizon has decided to cripple the bit rate / throughput for any video streaming service to any device attached to their network.
Video streaming services such as Netflix, Vudu and Hulu provide direct competition to Verizon's Cable TV, Premium Movie Channels, PPV and Redbox Instant.
With the demise of the FCC's Net Neutrality rules Verizon can and does pick & choose which fast Internet connections they are willing to support.