That's completely wrong. The PHB tells the players straight up that the DM might have changed the rules and to ask what changed.
PHB page 6 "Because there is so much diversity among the worlds of D&D,
you should check with your DM about any house rules that will affect your play of the game. Ultimately,
the Dungeon Master is the authority on the campaign and its setting, even if the setting is a published world."
5e DMG page 4: "And as a referee, the DM interprets the rules
and decides when to abide by them and when to change them."
5e DMG page 4: "The D&D rules help you and the other players have a good time,
but the rules aren't in charge. You're the DM, and you are in charge of the game."
5e DMG page 4: "The last part helps you adjudicate the rules of the game
and modify them to suit the style of your campaign."
5e DMG page 34: "
Feel free to change or ignore rules to fit the players' roleplaying needs, using the advice presented in part 3 of this book."
5e DMG page 235: "
The rules serve you, not vice versa."
5e DMG page 237: "Remember that
dice don't run your game-you do. Dice are like rules."
5e DMG page 263: "
AS THE DUNGEON MASTER, YOU AREN'T LIMITED by the rules in the Player 's Handbook, the guidelines in this book, or the selection of monsters in the Monster Manual."
Tell me again how the game doesn't tell the DM over and over again how he is in charge, not the rules.