Several of us have been doing this for years without incident. I suspect those who speak so strongly against it have simply never done it, and imagine all sorts of things that really don’t happen except with careless drivers who mess up whether they are braking with right foot or left foot. Plus there seems to be a strong anal contingent on this URL.
I just drove last week through Texcoco, a town adjacent to Mexico City, and I assure you I kept my left foot over the brake to minimize foot movement time. Those vehicles typically drive with a few inches between cars and any advantage is good.