Because the hoards of people who can't find the ` or | or $ on their keyboard outnumber competent people 100:1. I had this exact experience too, so frustrating. Moved to a strictly referral model where I pay my SWEs $10k if a candidate they refer gets hired.
A person who only has real industry experience can very easily have never needed git at all. I know this shocks people who only have hobby or startup experience but git works very poorly at large scale and there are many big organizations who don't use it either because their solutions predate git, or they are newer companies that simply have good taste.
I’ve been in dev since CVS was a thing and did migrations across all of them really, svn, mg and finally git. I’ve worked in a broad swathe of industries and never once over 25 years have I ever seen an org not using source code management.
One low point was an interview with a guy who connected with his current work laptop and couldn’t find the $ key on it for a basic scripting question.
I can’t make it make sense either.