Simple: we all know that Computer science is no more about computers than astronomy is about telescopes.

(Something like that can be said about mathematics, I am sure.)

When I was in school back in the 90's and worked for the computing center supporting Unix workstations on campus, it was always funny to get called over to the CS department to fix a professor's workstation and discover once again that they had zero clue how to use their machine. These were the same professors I had in my CS classes, who were fantastic. They were 100% theory and not at all practical, and actually weren't the least bit ashamed to admit it.

One of my professors answered “How do you go about debugging your programs?” with “I don’t debug, I prove my code correct before typing it in.” Not very useful.

I've worked with people a bit like that.

Yeah, I think it is similar to how some software engineers are more into writing tools and libraries than creating a product that common people use

Because something broke inside following the times in which they were requested to help with your "virus infected mouse device". (Sorry.)

Or those times "What do you mean do not open the virus? I tried to open it, I clicked on it a thousand times, nothing happened!". (Both are very real and lived, I am afraid.)

Oh, you computer scientists!