The video linked in the Twitter thread explains it near the end but I’ll summarize.

Rockstar used securom for the original disc release
Razor (an infamous piracy group) cracked the game shortly after release but only for Windows XP (Vista didn’t exist yet)
Rockstar released the game on Steam “without securom” but in reality is just using Razor’s crack
Fans eventually (like a decade later) realize there’s Razor signatures in the executable on Steam
Rockstar pushes an update with a new executable, however this wasn’t properly tested and is broken due to how the anti-piracy acts.

The game launches but similar to Arkham Asylum’s “broken” grappling hook or Serious Sam’s invincible scorpion enemies it messes with the player and doesn’t function correctly on purpose.

Really interesting video and once again brings up the ethics of stealing from pirates’ works as other comments have mentioned.