Likely the same reason why banks and other financial institutions still use COBOL and Fortran code written in the 1970s or earlier on archaic mainframes: Top management decided at some point it was too expensive to rewrite everything from scratch in some modern language for modern hardware, so they just limp along with what they have.
A 16-bit app written for Windows 3.x would almost certainly have to be rewritten for modern, 64-bit Windows.
Reportedly, they were restoring the comments of some deleted accounts for which they detected this.
That one probably got a rotten rating solely on the fact that everyone feels that anything other than a cheese ball, "man in a rubber suit" rendition of Godzilla is being unfaithful to the franchise.
Also, the "video telephone" that everyone always so desperately awaited from the future? Yeah, we have that; no, nobody uses it, because we can't be bothered to dress up for a phone call.
As usual, Republican states won't adopt this. And you can expect Republicans to appeal this all the way to the Supreme Court if it ever does get adopted, which the current conservative majority will almost certainly bend over backwards to find "unconstitutional."