I don't see any evidence of a huge number of people, that could otherwise contribute anything meaningful, avoiding Linux kernel because it's "hostile". They avoid it because they simply don't have anything meaningful to contribute, or are not able to contribute with the level of quality required in Linux kernel, or they are unable to handle the inevitable criticism.

Also, I'm pretty sure Linus has never used those words to tell people to get lost. Don't invent stuff. He might use strong language but in many cases it is humor or he knows the receiver personally.