And I have no objections to anyone defending a person in that situation.
Really? 'Cause that's not what you said. You said "the very idea of finding words spoken in your presence at a third party, let alone text on the internet offensive was alien and unimaginable". You said you found the idea that anyone speaking up for a third party, when the insult wasn't directed at them, was stupid. You have literally already expressed your objection.
Not that it'll ever happen mind you.
It happened in the past (though unfortunately rarely), and it happens today. You're complaining about it happening, and referring to people speaking up on behalf of others as "modern madness."
Life is cruel, short and unfair. And for most humans living on this earth it'll screw them over before they are even born by having them be born into the wrong place, social class, race, ethnic group etc.
And so we shouldn't try to improve society?
You're getting confused between "life isn't fair" and "the society you grew up in was shit." You said people are wasting time "in an ideological crusade to change the very nature of reality," but they're not trying to change the nature of reality, they're trying to change social behaviours. You do get that those aren't the same thing, right? That those social behaviours they're trying to change (it being acceptable to call people faggot or <removed>, for example) aren't intrinsic and inalterable parts of the universe.
By your logic, women should have just accepted that they were second-class citizens, and had fewer rights than men, and not complained, and never wasted their time or energy trying to change the nature of reality, since "life ain't fair." I guess the entire Civil Rights Movement was a mistake, too, since "life isn't fair", and they should have just resigned themselves to knowing their place. We probably shouldn't have bothered with the Magna Carta, either, or the Declaration of Human Rights, since "life isn't fair."