This comes across as conspiracy theorish, but sadly isn't if you consider Thumbtack/Nest? getting penalties & reversals within a week. Maybe it was a coincidence that they had GV investments? When a non-affiliated site gets penalized, Jon Mueller and Gary Illyes say "we can't 100% explain the algorithm's ranking decisions. Just publish more quality content", but when a GV company gets hit, Google acts quickly in rectifying the penalty.

The same for eBay's massive organic penalty after they published a case study showing that pausing their paid ads didn't hurt their business.