why are their defenders not indeed nasty?
That was what I used to think. Then I found out that some people just don’t want to know things. They are unwilling to accept certain facts or realities and when they lash out or defend, it is from a certain level of ignorance, not nastiness. This goes for so many other discussions as well, hashkofik, theological, and philosophical. Not everyone who says nasty things knows that their words are nasty. Some really believe they are speaking truth. And in person, there is often too much emotion surrounding these discussions for it to be seen so clearly.