Its great that some American Google workers have decided to unionise (in practice, a significant proportion of their EU staff will already be unionised), and they are right to point to ethical issues as the reason for doing so. In the medium term, we are going to see some sort of professional regulation in software engineering, if for no other reason than to ensure that Terminator and Black Mirror don't become a reality.
The situation with customers and users is different. They already have ultimate power over Google since they can simply go elsewhere. The best way that we can keep Google decent is by ensuring that competing services can emerge. Unionising customers/users would actually make them more invested in Google which would be self-defeating.