I originally did not use this approach because many pages that require translation are behind authentication that cannot/should not be run through these proxies.

Some languages are crowd-sourced with free labor, and they make money out of it.

You might try this extension: https://github.com/andreicristianpetcu/google_translate_this It does the same thing in the same way as Page Translator and likely will be blocked by Mozilla, but this is a cat and mouse game worth playing if you rely on full-page in-line language translation.