I said what seemed right from my point of view. Now I never thought that local members might be disrespected for posting in English. I agree that local board members should post in local language, because it will be easier for all members to understand the post there.
Now even if someone feels comfortable posting in English on a local board, your statement implies that he should be forced to post in the local language in the local language! However, since I don't post on my local boards, so don't worry too much about this. But still just giving my opinion.
Just explain to me something that I didn't understand: what was the purpose of a French user, writing in English on the French board?
If the language of the board is french, and your mother tongue too, why not write french?
Of course this can happen, in specific situations. I myself already wrote in English on the Portuguese board - I was replying to a user who asked something in English. I did it with pleasure and without any problems.
I just don't think it makes sense for a native speaker to speak another language on that language's board, without any relevant reason.