Speak as an English speaker but as somebody new to the site who after submitting various homeworks discovered another version of the site existed - this was infuriating and would be a very easy fix.

He isn't saying that feedback in english is a bug... I think he is suggesting that the text be changed from what it says currently which does not make it specific:

"All ideas and comments should must be in english"

and be replaced with:

"All ideas and comments must be in english"