For your second point: The intent of this article, which I hope you have read by now, specifically talks with people who say they are not being paid well working for Google as a contractor. They directly quote people who say they are not being paid reasonably for their work.
For your third point: Yes, I'm sure Google does business with unionized employees. This article is about a contractor, which is working for Google, using anti-union practices to prevent their workforce from unionizing because according to the workers they are underpaid.
And your final point has literally nothing to do with the article we're discussing or the entire argument chain we're in right now.
This constant insistence that google contractors are being paid $30K to do work that $171K engineers are doing in the same geo area is totally false. That does not happen. I am open to a specific example, but I'm not aware of one.
To be a google contractor you need a contract that has google's name on it (or Google LLC etc). That is the literal definition of being a google contractor. You get a 1099 from google. If this describes you - you are, on average, paid well.
Google flies on US airlines with highly paid and unionized pilots - I don't think they care.
Are you confusing google contractors with employees of a large non-google business?
I'm not aware of almost anyone (network infra contractors / team build soft touch providers) who historically haven't been paid very reasonably for their work working for google.
And Google does business with contractors who have unionized employees. I'm not aware of them caring too much about that either.
Google does thousands of H1bs and has something like a 99% approval rate even under trump so they don't mind working with international folks.