Ouch. I was really hoping this wasn't so common, but I guess it is. I'm sure they heard somewhere that "joins are expensive" or something along those lines, so they solved it!
There are also other "lets pretend we have big data" patterns I've seen. Running something like AWS Athena or Hadoop over and over, for less than a couple gigs of data that would fit into memory on a laptop from 15 years ago.