As one example, which I dredged up just now from an online comment that dates to a debate Australia had several years ago: Someone complained that too many people "use the word 'bigot' as a one[-stop] word... for all ideas they oppose." In this person's narrative, Australians who believed that marriage should be limited to a man and a woman were "minding their own business" when suddenly the left-wing decided they were bigots, which amounted to an "attack" on those people. "Once they [the left-wing party] decided they supported the redefinition of marriage, all others still opposed became a bigot in their world view," per this complaint. But — to bring it back to what you were saying in your article — presumably individuals and organizations have reasons for changing their minds on an important issue. If someone calls a set of ideas "bigoted," quite likely they have a basis for arriving at that judgment. "Bigot" is not, in fact, solely a smear for "an[y] opinion the 'progressives' disagree with."
It's adjacent to the debate over "cancel culture." No one wants to be called a bigot or similarly criticized; they probably aren't ready to do the work to change; and rarely are they willing to face public consequences.
The catchphrase "You're the real racist" is used in a similar context. You identify something you believe is racist. A common response is "you're the real racist" because — in the way the person saying so wishes to cast the discussion — no one was using the word "racist" until you showed up. In the logic of "I know you are, but what am I?," you "are" whatever you accuse someone else of doing. Probably you can argue your point about why you believe the original thing was racist, but arguments are irrelevant in this type of interaction. The person will accuse you of doing an ad hominem regardless of what arguments you supply. As long as your conclusion is something is harming people based on race and we should acknowledge it, withdraw support from it, and behave differently in the future, racists don't want to hear what facts and logic are behind your conclusion because they refuse to let you make a prescriptive statement against racism. The quickest, dirtiest way for them to argue back is: You used a slur against my political side. You said "racist." Even if you carefully avoid that word, it doesn't help much, because then they'll adapt their response to be "you are a racist for mentioning race." You are definitely not ad-homineming them, but they will be delighted to say that you are. After all, if they let you talk about race, and if your reasoned conclusion is that something bad is happening and needs to change, you have challenged the power-stance they'd like to have on these matters, and indirectly they hear that as you calling them a racist.
Personally, I encounter this dynamic in the context of anti-transgender antagonism. A Twitter search for the terms [bigot "gender critical"] pulls up recent discourse ("discourse," in the Twitter sense). https://twitter.com/search?q=bigot%20%22gender%20critical%22%20since%3A2020-01-01&src=typed_query&f=top Trans people easily perceive that anti-transgender people are bigots. (I take this as settled fact. It's not ad hominem. There are a thousand arguments to be made about why an anti-transgender position is a bigoted one.) The anti-transgender people respond, No no no, we have arguments behind our feelings and beliefs about you. When you call us bigoted, it is a heinous slur. You have wounded us gravely, and we shall never recover. A trans person can point out that these anti-transgender arguments are made of crap and fascism — that they are not merely accidentally harmful but are linked into complex, established misinformation campaigns, and thus, while they are intellectually defeatable, they have already been intellectually defeated a million times, and so it is a massive waste of energy to be polite toward bad-faith political antagonism — but having the argument, or saying why you don't want to have the argument for the billionth time [because it involves talking to a bigot], does no good. The bigot is not able or willing to change. Ultimately, they are only able to say: You "ad-hominemed" me as a bigot.
