Don’t get ticked at the kid for writing bad poetry. As QuickSilver said, he was just trying to cope.
Don’t get mad at the kid’s parents for selling the bad poetry. I’m sure it helped with the medical bills, and it’s hard to blame them for that.
If merchandising the bad poetry bothers you, get angry at the publishers. But wait! They wouldn’t have published it if people weren’t buying it. At my bookstore, I had people buying a half-dozen copies at a time. Are you saying the publisher shouldn’t provide the public with what they want?
It sounds like Acqua Minerale’s real problem is that a whole lot of people have bad taste in poetry.
Wait. That was a pretty crummy sentence. Here, let me fix it:
It sounds like
Acqua Minerale’s
real
problem
is that a whole lot of people
have bad taste in poetry.
There. Now it’s poetry. All is well.
Honestly IW you have a good point. True, his work is utterly without the slightest redeeming merit: boring, incredibly trite, glurgey, overpraised, repetitive, and lets not forget voluminous brevity is the soul of wit. But, I was forced to falsly praise* loads of crap from many genres during my years in the bookselling industry, but I didn’t hate all of that crap with the same venom that I have for poor dead Mattie’s handiwork (I hated it equally during his life, BTW).
I am not a poet, BTW, nor do I have any personal stake in book writing that would embitter me towards a commercially sucessful book. I’ll have to chalk it up to a personal failing of mine since there really isn’t a logical explanation. Although, while it isn’t a defense, all of my compadres on the blurb-monkey team hated his books with an equal passion. There is something grating and ire-raising about something so awash in sheer badness being so sucessful.
*but I maintained the shreds of my dignity by damning it with faint praise: “this book is long-awaited!” “more of the same from Author X!” etc. Blurb readers, take note. 
“Bad taste” is a bit of an understatement, but that sound fair enough. It upsets me to my core that people like that sheer and utter crap.