Hmm, I guess I see what you mean. To me the ads feel like an integral part of it, like the cash/card registers in a McDonald's, but when you point it out I see it can be a separate component. I suppose it would be like McDonald's manufacturing their own registers and refusing to sell them to competitors. There are a lot of register manufacturers, and a lot of other ad platforms, but indeed on other ad platforms you don't reach the Facebook users that you want to reach, so perhaps there isn't really any other option than to run Facebook ads.

I guess I also saw it differently because it feels like a free speech argument: why does FB have to give competitors a voice? But it's not about having to give someone a voice because they claim it should be a free (as in freedom) platform, it's for maintaining competition.

I think I've changed my mind. As you see I'm still thinking this through (out loud) but I suppose it should indeed be different entities, even if the to-be-separated ad business is selling "real estate" on Facebook.