Being a "non-profit" doesn't mean the company "shouldn't make profit" ... It means that the owners/investors don't earn anything extra based on profit. The organization itself still needs to be financially sustainable.
As shady as Mozilla is, they're competing against a functional monopoly, so the playing field is hardly fair.
Fair enough. Although, for those reading at home, I'll reiterate the distinction between nonprofit and charity; all charities are nonprofits, not all nonprofits are charities. Research universities are an example.
On that note, I guess I'm enough of an academic to not consider grants a "gift" ... It's not consumerism-driven revenue, but it's hard to call it a gift when you're on the hook to produce something (research papers & prototypes) that you then turn around and use to sell for more revenue (in the form of grants).