This is sort of accidentally technically correct. It's not always right to use /dev/urandom on Linux. During system startup, it does bad things if the entropy

This is sort of accidentally technically correct. It's not always right to use /dev/urandom on Linux. During system startup, it does bad things if the entropy pool hasn't been initialized yet. So yeah. You shouldn't always use /dev/urandom, if you are writing code that's designed to run during system startup. In every other case, you should use /dev/urandom. It's a super-minor technicality preventing this article from being 100% wrong. Please don't follow its advice.