My wording is pretty clear, that’s no claim to have proof. My working understanding is that .rc files are common for shell init. If it turns out that .rc files slow down any shell du jour significantly, then TIL, I don’t know much about the inner workings of shells and haven’t had a practical reason to learn.

In any case, I’d like to apologize because I clearly offended you somehow, despite being a fellow zsh user and for that I am sorry.