Thats a pretty ignorant statement. I'd wager that there aren't many people who could/would put the same effort into self studying that would be required to pass a CS degree with decent grades. They also would probably not learn a lot of stuff that is not interesting to them, while CS students have no choice than to go through the materials. As an employer this also tells a story about who is taking the easy route vs working through a complete program over the span of years. Obviously there are exceptions, but when there are a lot of applicants for a position, it's just an easy filter for employers.