Guess The Elo

white is 3000 and black is 1100

white is 3300 and black is 1100

white is 2790 and black is 1100

White did play 2.d4 and Qxd4 which is not optimal, but often times players do this in online chess, mainly to throw opponents out of theory. These two moves don't mean much on their own. I guess that the other reasons why you think that white played badly are that he played f3, didn't develop his kingside bishop and knight and then blocked his bishop with his queen. However, none of these moves are mistakes. Often times when you are castling queenside you want to play f3 which prepares g4, it stops Ng4 and it strengthens the center. Waiting to develop kingside bishop and knight is a pretty common idea in these kinds of positions where you castle queenside and your opponent castled kingside. For this reason it doesn't matter that white's queen blocks the bishop, you don't plan on moving it anyway (sometimes you will even put the bishop on h3 or b2). Also, you want the queen on the kingside, that's why Qe2 is a good move. Because you want to transfer the queen to the kingside. So, why didn't white play Qh4 or something like that instead of Qe2? There are 2 main reasons. First reason is, white wants his queen behind the pawns, so that the queen doesn't block the pawnstorm. The second reason is that white's queen can get harassed if it is in front of the pawns. Queen is safer behind the pawns but it is also just as deadly when it is behind the pawns, attacking from distance. White made no mistakes in this game as far as I can tell. 

When it comes to black's play, the only mistakes I can see are allowing white to play h6, playing Nce5 and Qb7 (I think these two moves are a waste of precious tempos). Black could have tried to justify Qb7 by putting a rook behind the queen but he never did that which means that black played Qc8 and then Qb7 for nothing. His plan was apparently to put pressure on white's d5 pawn (which is a ridiculous plan in this situation. Black needed to attack white's king by a pawnstorm of his own). In my opinion black should have first marched his pawns and only then decide where to put his queen depending on what files get open. That way you save a tempo when moving a queen, and your queen move itself will maybe come with tempo. Black didn't pose any problems to white in this game. Black's attack was so slow that white could do whatever he wanted and white went straight for the jugular.
However, black didn't blunder any material in this game. He developed his pieces, castled, he was simply outplayed by white. I don't know why you think either of those 2 players are below 1300

let's be honest, darkbrah's guess is obviously the closest

2851 851