Yes, if you compile your own binaries, audit the source code, and for good measure audit your compiler and the system you are using to compile it, then there is a meaningful difference*.
Since 99% of users don’t actually do any of that, then in practice there isn’t actually a difference.
* I am aware that there are shades of grey between the scenario I describe and proprietary software - I am just being hyperbolic for rhetorical reasons.
> Since 99% of users don’t actually do any of that, then in practice there isn’t actually a difference.
I understand the hyperbole, but in practice we have strong evidence that MS is willing to intentionally use their OS against you, while we don't for your typical linux OS. That really means a lot.
When linux distros disrespect their users even a little (see for example https://www.pcworld.com/article/436097/ubuntus-unity-8-deskt...) users really don't put up with it and they can switch to another distro with very very little effort/change and even have the ability to modify the source and fork the OS. That helps to keep people a little more honest.
The backdoored compiler problem is a bit harder. We can write our own, but it's turtles all the way down. Increasingly we also have to put a lot of trust in our hardware. There are only a small number of companies making CPUs and wireless chips. I imagine they're under enormous pressure from governments to compromise the privacy and security of the people using that hardware and we have less trust in our own devices the more we have "trusted computing" forced on us.
if you're paranoid about the distribution of your pre-built distro you can compile everything by hand and some do that for fun.
so putting them on the same pedestal is weird mind gymnastics.