Does anyone know why "We hear you." is an incorrect translation for this?
to listen = écouter
to hear = entendre
We hear you. = Nous vous entendons.
i would complain about how overly picky the software is on spelling, especially for the translation into english but it wouldn't do any good.
It's simply a different grammatical construction in French. Conversely, you can ask yourself why we need a preposition with "listen" (to) or "look" (at) in English, where it's not needed with similar sense verbs like "hear", "taste", "smell", "feel", or "see".