The majority of the Internet's routing and switching architecture is BSD based. Historically it had the most stable and performant network stack of all the OSs.
I used it extensively at one job in a previous life when I was a network appliance developer. It was rock solid and lightning fast. Tried it as a desktop at home and had a terrible experience.
The little differences in the Unix commands used to drive me nuts as well...
It very well could be these days. It could also be default settings that are better on Linux for certain activities. The network stack is highly tunable.