I have occasionally voted down a patronising or blatantly incorrect answer. I have never been asked why, so I have never explained. If they did ask, I would happily explain.

Yes, I have a couple of different times. I would usually be willing to express why if asked. No one has asked so far, which I've actually been glad about. Sometimes it's not really necessary to vote someone down and may actually be better to just ignore them or like was said before bypass them.

It may be as Walt suggests if you are on a septic system, if not, you might try some baking soda in the drain then Apple cider vinegar poured on it.....it will bubble up so be careful how much you put in!