By comparison, it's like the ticket repas and chèques vacances in the French companies—getting subsidies for food and vacations would look quite odd to Americans.
Different cultures, different perks.
Silicon Valley companies frequently subsidize food for their employees.
If you feel that strongly about a charity double your own donation.
The company essentially gets to offer me more money at no cost to them if they structure their compensation this way. You could be very transparent with this and simply allow employees to direct the company to put money into charity (with the tax going to the charity instead of the government) but it's probably easier for the accountants to simply do matching with a cap, which is why you see companies do it this way.
It boils down to a tax write-off that allows the company to look charitable. But there's a lot of benefit along the way, so who cares of the motivation?