To be fair, conceptually the concept of a CEO of a security company with no social media presence at all is not surprising, speaking from my experience with people in this field.
Interesting, I have little idea how the field really works. I guess there must still be some kind of internet presence, maybe not through a typical social network ?
No it won't, that's a really odd take. Perhaps if you want a job in very specific sub-section of cyber-espionage stuff, you might have a problem with existing on social media (although I doubt it)
But the idea that general IT security companies have a reduced chance of hiring someone based on their information being on social media is... not the case.