I'm by no means familiar with labor law, but are companies (in Switzerland or the US) required to actively support unionization? It seems like it would be one thing to actively oppose unionization, and another thing to require the organizers to provide their own meeting rooms, space, etc. Looking at the article, it seems like this is the latter.
That said, it's still newsworthy. Forming a union is usually a battle of public opinion. As an organizer, it's likely in your best interest to say "hey, look your company only wants to explain unionization if they can help sculpt the message" as exactly the sort of behavior that would drive you towards having a union.
TL;dr- Unionization is frequently about optics, and these aren't great optics for Google.