People see themselves so differently from reality. In fact, due to the filter of our brains, we may not actually ever experience reality.
I was listening to some podcasts as an anti-Mormon and an ex-Mormon were discussing their stories. One guy says he "is not into the ad hominem" (attacks on people disqualify their argument, rather than their arguments). Frankly, I started laughing out loud. This is a man who has literally screamed at me on the street calling me a "deceiver". I handed him a flyer I wrote specifically addressing an activity he likes to do to try to make his point, mostly with Mormon youth. My 2 page flyer lays out every known historical account of the subject, providing quotes and references so folks can look them up themselves. It doesn't mention him or even discuss anti-Mormon claims, so it cannot be seen as a personal attack. It simply lays out those historical figures with first hand knowledge, and the statements they made. He refused to discuss the citations, but instead judged me and called me a deceiver. I am pretty sure that is the definition of Ad Hominem argumentation. It is also technically the logical fallacy of "poisoning the well".
Here is a guide to detecting an Ad Hominem attack:
If the response describes how unenlightened a person is: "They lack the holy Spirit, so they don't understand ...X" In other words, ignore their arguments because they don't have divine guidance. Sort of the defintion of a circular argument ("trust us, we have the Spirit, they don't") with ad hominem thrown in ("Disregard anything he says, he does not have the Spirit".)
Or they beg you not to read or discuss something because of a supposed defect of character: "He is a deciever (liar, fat guy, bald, has freckles, Body odor, etc.)." How does that impact the argument? Isn't the whole point of examing an argument to find out if it is valid? If so, then this type of attack is just to try to avoid having to respond to the questions such a person may create.
Or they tell you the person does not have the right credentials: "He/she does not represent the Mormon Church." Translation: "Their arguments are probably better than what the Church would make, and I don't want to have to deal with them." Sort of the back-handed compliment of the first set of excuses.
Lastly, if you hear someone say something like "I (or he or they) used to be a Mormon, and should know the truth about them." Run away. This is an inverted Ad Hominem attack. It presents as a sole qualification someone's pulse during a period of time. It tells you nothing about what they know, their attitude or participation while a member, or their current expertise on any subject. It is designed to try to cancel out listening to the arguments of Mormons by indirectly attacking their integrity, and once again avoiding discussing the merits of the arguments being presented. If presented as the primary, or in some cases the only, qualification, you can rest assured they don't know anything of a substantial nature. And lest that be taken as an ad hominem attack, I would say check out what they say. If they say Mormons officially believe or did believe in things like God having sex with Mary, or the Adam God Doctrine, or that Joseph Smith practices polygamy simply as a pervert, then there are plenty of non-LDS and LDS sources which can easily refute such assertions. Then you can draw a conclusion about the reliability of this person as a source of information, and not have to engage in ad hominem attacks.
A teacher soon learns which students do their schoolwork because they understand the subject matter. If they constantly produce poor work, the teacher knows what to watch out for, even as he/she reads a bad paper from the student again. The student gets to make his case, he just loses trustworthiness when the work is consistently bad that suddenly he is going to submit something brilliant.
So it is with those who claim to hate ad hominem arguments, and yet resort to such when confronted with arguments they cannot answer. Beware.