You stretched that tweet pretty far. It's clearly nothing more than an anecdotal counterexample. I'm not sure how your paraphrasing quote ended up becoming such a sweeping generalization.
Worked with several highly competent people in tech and infosec with music degrees, liberal arts degrees, no degree...
I'm not saying music degree people can't be good engineers, but saying "no infosec people have CS degree" is plain absurd.
A few folks got Physics degrees, but the vast majority of people I know left school to work and have not finished. Myself included.
The other very common backgrounds that I encounter is people who served in the military and people who backdoored their way into it from being sysadmins.
She could have her degrees for computer music for all we know, which at the time she got them probably would have required some serious programming chops.
When I was working at Cisco pretty much all InfoSec people I know had a technical degree, from CS to EE to sometimes Mathematics.
I'm sure there are some outliers, but saying "no infosec people have degree in CS" is just plain ridiculous.