I think the writer has misunderstood the word "schadenfreude". He seems to understand it as "joy you get from hurting somebody else".
I always understood SchadenFreude to mean "the joy you get from somebody else's loss or other misfortune" - with no active participation by you in causing it.
If your car-addicted neighbor annoying the whole neighborhood with his 400 HP engine would run over his own cat, you'd experience 'Schadenfreude'. You'd still feel sorry for the cat though ;)
I hope this article is not a sign that we are losing the word in English to people who want to affect erudition, as we don't have a good native substitute (and that is not because English speakers do not have such emotions!)
Now, if your acquaintance is obnoxious or is putting everyone down for not being able to afford their dream vacations, then yes, Schadenfreude would apply.
In more general terms, you don't feel Schadenfreude whenever something bad happens to someone. There has to be a sense of "Well, that guy had it coming".
https://www.quora.com/Why-do-most-American-dictionaries-prov...
Feel free to read the full explanation on a pretty awesome example: https://en.wikipedia.org/wiki/Donaudampfschiffahrtselektrizi...