I'm seeing mainly trash from Japanese companies that are Japanese products with Japanese labels. It's easy to recognize. Externalizing blame isn't the solution because it's not the problem.
Currents likely help carry trash away from certain regions. Japan's east coast isn't really being affected by trash that would be coming from, say, China, because currents don't carry most of it to our beaches. It's stuff being washed out locally and brought back by waves here. Much more is likely being passed out into the middle of the ocean.