One of the more common responses to the Dutch Defense is as seen below:
[FEN ""] 1.d4 f5 2.c4 Nf6 3.Nc3
I understand the logic behind this fairly well. White establishes a strong queenside presence and is free to bolster defenses in the center with their knight without fear of blocking their own pawns in. However, the following sequence of moves is almost never seen:
[FEN ""] 1.d4 f5 2.f4 Nf6 3.Nf3
I understand why this particular version is so rarely seen: the e5 square is given a needless amount of protection while leaving e4 defenseless. However, in general, you still never see players at the master level try to go for f4 and Nf3 against the Dutch, regardless of how the first few moves shake out. Why is this? I know anecdotally that it's good practice to put your pawns in front of your knights, but if that's the case, why do it only on the queenside and never on the kingside? In the first example up there, white usually plays Nf3 anyway, blocking their own pawn in. Why does this double standard exist?