One of the best ways to avoid devolving into a monstrosity is to allow oneself to note it as it tragically happens to others--maybe even as you try to pull them back and they only snarl all the more ferociously--and then be mindful of the signs that they should have seen and which you could see in yourself, should they start to arise.

For instance, if you quoted, sans context, Popper on the paradox of tolerance, instead of quoting Desmond Tutu on humanity, it would be a worrying sign.