It's a loaded term for sure. Still, to what extent does "minding one's business" excuse such behavior?
Your rights end where mine begin. That's generally a good measuring stick.
Is it legal? Depends on the country.
Is it "moral?" To the individual probably not, but that's not anyone else's concern. Moreover, some cultures (Japan) don't demonize sex and porn to the extent that other countries do. So practice some cultural understanding.
Is it tacky as hell? Without a doubt, but again, that's judging by our culture and values.
I always found amusement with the "How do I explain this to my kids?!?!" I dunno about you guys, but I've watched porn since I was in 5th or 6th grade, and I turned out just fine and dandy. My parent's didn't really need to "put it in perspective" for me or anything. But if you kid has questions about it, explain it maybe? That's kinda part of being a parent. The biggest bitch about gay marriage were conservative (not politically, but the "not so outgoing" meaning) parents were bitching about having to explain two dudes marrying each other, and everyone said "be a parent and explain it!" Well, this isn't all that different, IMO, if that's your argument.
Then the whole idea that someone can watch porn and trigger someone else to do something is just silly. That's the ol' school shootings happen because of violent video games and movies, then the whole GamerGate bullshit, about how video games make gamers sexist or misogynists. Didn't fly then, doesn't fly now.