The DM can say anything they want. They can say "you must stand on your head when you roll a d20", or "warforged need food and water".
You can say anything you want. You can say "no they don't" or "my head is a pineapple".
In D&D, however, the generally agreed upon convention is that the DM is in charge of what happens in the world that they are "running" -- the game world.
Assuming you are agreeing to this convention, then the DM can say anything about the game world, and that holds in the game world.
It is also, generally, a convention that the DM shouldn't use this first granted ability capriciously and without forethought. The rules of D&D itself should, by default, be what you are playing by, and the players should have an idea of how the world works by looking at the rules.
After all, you are playing D&D.
All of these are no more powerful than the convention, but a game of D&D generally requires a DM and a game of D&D generally requires players. Unless both the DM and any players can come to an agreement about the convention and what is "fair", there won't be a game of D&D.
In other words, you are free to walk away, and find another DM. You are free to recruit your fellow players to also walk away. That DM is free to have whatever rules they want.
If you where the DM, and asking "should I make warforged eat and drink, because I think they are over powered?", I'd say "no, that is a bad idea; the non-eating/drinking of warforged is pretty core to their narrative, and is a relatively minor power in a fantasy orc-killing adventure game: but conventionally you have the right to say that, however you may not have players shortly".
But you aren't the DM. You are a player. So you have to decide: is the game otherwise good? Is there a sign that this is going to be a continuing problem, where the DM arbitrarily changes the game rules on a whim? Can you find a game where the DM doesn't do this?
No D&D is better than bad D&D. And leaving a game is generally irreversible. So I'd advise saying "If you are going to rewrite my character, please do so before we start playing. But if this is important to you, I'm game.", and keeping an eye out for this problem repeating.