Lyxen
Great Old One
Stuff like this belongs in the Players Handbook, not the DMs Guide.
No, they don't. First, it's an OPTIONAL rule, as written, and customisation belongs in the DMG by your own admission below, moreover, this concerns NPCs and Monsters. What business is this of the players ?
Also, social reactions, stealth rules, athletics rules, and so on, needs to be in the Players Handbook.
No, again, they don't. Sorry, but the standard loop has just the players describing their actions. What business is it of them how the DM manages the world and the NPCs ?
Everything one needs to run a game belongs in the Players Handbook.
Seeing that the DM runs the game, this is absolute, total nonsense.
Everything in DMs Guide is more about modifying the game.
That is your own opinion, and it has zero value for me.