The idea is that big companies have money to spare and small companies don't. Therefore big companies should be paying for the benefits they are receiving to support the tools they rely on.

I'm not convinced personally, but I think that's the idea.

I don't agree with the parent's solution. IMO one of the things that open source software has done right is that it mostly doesn't distinguish what you can use the software for.

However, I understand the point being made. It's essentially a tragedy of the commons argument. Because the companies that get the most value from open source are also often the ones with the greatest resources to give back to open source projects if they chose to, they have a moral obligation to do so. There's also a sentiment one often hears along the lines of: I'm fine with people using my work for free but I don't want them making money off it. (This is essentially the basis for Creative Commons' non-commercial variant).

So it's not so much that large companies are actively hurting the projects--though you could argue that hosted offerings compete with the projects themselves. But that they often don't help in anything like the proportion that they benefit.

One might believe that OSS's raison d'etre is to increase equality in economic opportunity. If you see OSS dev that way and you see corporations like Google and Facebook as opponents of that cause, then if you agree with GP's statement on who the beneficiaries are, you might also agree with GP that there's a problem.