Yes, it's a form of signaling. It's like a milloinaire showing "I have so much money that I can dump 10k on a Rolex and not even think about it", or a billionaire showing "I have so much money I don't even need to dump 10k on a Rolex to show how much money I have". These guy's version is "I'm so technically accomplished, that I can tell you I don't know X basic thing and you'll interpret it as a sign of my genius".
That's ok. In our society we attribute too much importance on money, I don't mind if the likes of Stallman and Linus get a bit more fanhood from the wider society than they currently do.
I think Linus and Stallman don't have disdain for "civilians". I think Linus in particular has deep disdain for people who pretend to be competent and then are not up to scrutiny; but he doesn't have those blowouts with dumbasses that he doesn't work with.
On the other hand, someone who strikes me has having universal disdain is Carmack.
Why am I am not good at excel, it is because I am the person who tends to fetch the data from the different systems and consolidates it for the analysts to analyse and some do use Excel to analyse the data.