This sounds more like a spin-off of the old investment adage: "Buy stock in the products you actually use." If you spin that argument slightly as a proxy purchase, it makes sense that VCs would be investing in the products that their other startups are using heavily.
As an super-small-time investor who only owns stock in companies whose products that I use and enjoy, I can't knock them for it. For me, the logic is that whenever I tire of using something or no longer find it valuable, presumably I'll have early insight to sell the stock before the rest of the world catches on. I don't know if that same logic applies to proxy buying, but I suppose if you're intimate enough with your companies to know if they're abandoning Github for something else, as I don't know if pulling venture capital is as easy as selling the stock.
> as I don't know if pulling venture capital is as easy as selling the stock.
There's generally minimal liquidity. During a round, an existing investor may have the opportunity to sell some shares to new/other investors, but if she knows something that's not coming out during diligence, there's definitely something fishy going on. If the round is shaping up to be a major up-round, maybe an early investor wants to lock in a good return, but that's beside the point here. And then of course if things really aren't going well for the company, you're looking at the bad kind of liquidity event--a liquidation.
So if a VC wants to pull out based on a negative hunch, it's probably either impossible or the signal itself will doom the company if it wasn't already doomed.
As an super-small-time investor who only owns stock in companies whose products that I use and enjoy, I can't knock them for it. For me, the logic is that whenever I tire of using something or no longer find it valuable, presumably I'll have early insight to sell the stock before the rest of the world catches on. I don't know if that same logic applies to proxy buying, but I suppose if you're intimate enough with your companies to know if they're abandoning Github for something else, as I don't know if pulling venture capital is as easy as selling the stock.