Those are fairly indistinguishable. It's when they start removing letters from words to save... debug symbol bytes or something? That's when c-style naming annoys me.
This is also my pet peeve with a lot of code as well as commands like
npm -g i package-name
Like why would you teach people to do this? I understand people needed to save precious bytes in the sixties so we have cat and ls but saving 192 bytes or whatever with shorter variable names is not a worthwhile tradeoff anymore.
In their defence "hi" sounds very much like "high" in my mind's ear and "lo" like "low" :)