I found this on skeptics stack exchange. Supposedly, it's a hoax/urban legend that goes back way before the internet. (The entire stack exchange page on this topic is fun to read, btw)

The quote originally came from Prof. George T.W. Patrick of University of Iowa, who translated an ancient stone tablet into modern English and published in "Popular Science Monthly", May 1913. The full text of the original can be found online at archive.org: https://archive.org/details/popularsciencemo82newy, page 493.

One writer found this same quote in a slightly earlier source dating to 1908.

Yet another writer noted that there was no Chaldea but ...

... there was a stele of a King Naram-Sin of Akkad which has been exhibited in the Istanbul Archaeological Museum since 1892. The inscription on this stele is fragmentary and has nothing to do with degeneration.

https://skeptics.stackexchange.com/questions/4923/was-this-quote-on-a-clay-tablet-about-unruly-kids-written-by-an-assyrian