A software engineer without "soft skills" is 0.1x engineer.
We all know this guy.
The one that you make sure to never talk to customer. The one you always need to ensure you approach carefully. The one who's "not good with people."
Yeah, that guy.
Software engineering is fundamentally a team sport. Even if he is very fast at typing in and recalling algorithms from memory, he'll make the entire org around him 1/10 as effective.