Not surprised. Tech companies (Facebook and Google in this case, and probably others) have been known to retain Pinkerton agents to monitor employees. Yes, those Pinkertons. “Among other services, Pinkerton offers to send investigators to coffee shops or restaurants near a company’s campus to eavesdrop on employees’ conversations.” https://newrepublic.com/article/147619/pinkertons-still-neve...
Several years ago, I started working for a company that was in the build up to a Yea/Nay vote for joining the union. During that time, 2 "goons" showed up at my apartment to discuss the benefits of joining the union and why not joining would be bad. However, these very "intelligent" goons showed up during the day, you know, working hours where I had a very low chance of being home. I don't know if they were just that dumb, or if they were trying to influence what they thought were family members. Instead, it was my flatmate from England. She told me just laughed at the thought of me joining a union, and not so politely told them to bugger off and closed the door on them. Ultimately, the vote failed miserably.
All of that to say, that I'm not surprised that anti-union shenanigans are at the same level as the pro-union shenanigans.