I don't get why the author is surprised that the c++ stdlib calls into the libc to get the current time, or opens /dev/urandom to seed the PRNG on unix, or uses

I don't get why the author is surprised that the c++ stdlib calls into the libc to get the current time, or opens /dev/urandom to seed the PRNG on unix, or uses pthreads. It seems that the author doesn't understand the relationship between language libraries/runtimes and operating systems.