[orestarod]

Even if you, specifically, cannot check the entirety of the Linux code, at once, right now, the Linux kernel code is open for checking and auditing. Anyone can check what code is written in it, and numerous experts have done so independently. Moreover, every single change in the Linux kernel is incrementally recorded and documented, so every change was audited and evaluated all on its own, when its commit was introduced. Like a blockchain, you can at some degree trust that the code written before you started checking things has been adequately audited by experts, and you can continue the trend from this point onward.

None of this can happen or has happened with Windows. You gotta trust a company firmly shut to the outside world.