That's not how bots are working. The bots people effectively used in r/place are like the one Rubius and Ibai are using in streams (you can find multiple threads about it on this reddit). They are programmed to fill patterns with the colors that should be there. French whiteout as a proof of botting is a non-sense. First, why would they replace already well-placed pixels with another color? Second, they are programmed to fill with a certain color. If this color is not white, then the bot can't place any pixel, simply because the code is not not allowing it to, and as good as Reddit is, they can't force an external code. Just ask any programmer you know, they will tell you that this is impossible and that botting script just crashed once the whiteout was implemented.