> They followed the process for forming a union in the US.

They followed a process. Secret ballots are also an established process. From your own link:

> Since the National Labor Relations Act (NLRA) became law in 1935, card check has been an alternative to the National Labor Relations Board's (NLRB) election process.

My understanding is that a secret ballot election is actually the more common scenario.

> The claim that the Foundation totally supports the right to unionize but wants to hold a secret election would be a lot more credible if this happened before the workers had a supermajority (!) of signatures collected.

Do you really envision a situation where a supermajority of signatures were collected from fully non-coerced and well-informed employees, but some union-busting magic is going to cause them to lose a secret ballot election?