Verizon provides what is essentially the on/off ramp to the Internet Superhighway. Just because the speed limit on the ramp is 150mps, doesn't mean you can actually get 150mbps elsewhere on the network, particularly those parts of the network that Verizon doesn't control (i.e. most of it). To reach a Chinese web site you probably go through at least a dozen 'hops', perhaps more, any problem or bandwidth limitations at any of those intermediate points, and your usable speeds fall through the floor.
So while it is quite possible that there is a problem, it probably isn't on a part of the network that Verizon provides. All Verizon provides is the on/off ramp. not the highway itself.