Eh, being fair, TF2 became free to play after a while, so at least by spending some money on cosmetics, you would be directly supporting what at that point was otherwise a free game. But loot boxes are still a janky and arguably outright bad concept due to the sheer randomness and how stupidly expensive rarer (and still entirely virtual) items can get.
One of the things I'll say Overwatch originally did better is that, if they were gonna have lootboxes, you could at least get lootboxes more easily and not need to pay any real currency to obtain or open them.