Why do people premove Bc4? What are they going for here?

This has happened to me at least three times now. I guess the opening is called the "Göring Gambit," but its a pretty normal e4 type of opening. ...

In positions like this, after white's c3, I pretty much always play d5, but I have had at least three opponents premove Bc4 and then I just take with my d pawn.... what the heck did they expect me to play??

Idk for this opening, but when the D pawn is not on d5, bishop C4 is meant for attacking the weak f7 pawn.

They were expecting you to play dxc3 and after Bc4 cxb2 going into Danish gambit type of sacrifice.

@sanjey2009 Yes, I know what it is normally for, but I am wondering why people premove it so often... Even 1850's premove it... It is as though no one ever played d5 against them before, but that seems very strange....

@Dario19503 That makes sense, but I am very surprised that dxc3 is so common to them that they even premove Bc4...

Stockfish recommends dxc3, but I think its a terrible human move because it just gives them free development...

It's all pretty standard stuff. And I'm amazed that you're amazed (how do you expect someone to respond to 4 c3?).

Obviously they should not premove. They do so cause they just gambited one pawn and want to act dominantly I guess. Or because it's bullet if it is.

@MrPushwood I expect them to respond with d5, because that's what I think is the best move.

@Folichon It's 3+0 blitz.

I just checked on Lichess DB and Bc4 is the 5th most popular move in the position. More popular than Nxd4 or cxd4 just to notice.