Why would you play dutch in the first place?

Honestly the Hopton attack is hard to play against, as it's counter-intuitive to the Dutch style; at least, that's my experience. So instead, I just avoid all the hassle with 1...e6 like others have mentioned in here. 

2... h6 must be playable but there is such a maze of variations after 3. Bh4 g5 4. e4 it becomes impractical for everyday chess. 4. e4 Rh7!? 5. Qh5+ Rf7 6. Nf3 Nf6 7. Qg6 Nc6 of Black Dog video fame and now White has many moves but I couldn't find one leading to a clear advantage, and 4. e4 Nf6 5. e5 e6 6. Bg3 f4 7. Bd3 d5 were ok for Black last time I checked but this is insanely complicated to maintain these lines in a repertoire for an amateur. The more reasonable 4. e3 must be +/= but as they say, obviously not terrifying, so suitable for both colors.

And as to why to play the Dutch? Because it's heaps of fun! Who doesn't love to attempt to blow their opponents off the board with the black pieces?

I love it not only for the double-edged, risky style of play that it often brings, but also because when you play the Dutch, you tend to know the theory better than your opponent (unless your opponent is an opening wizard, in which case, it's a good learning experience), as most players of 1. d4, 1. c4, 1. Nf3 etc. do not prepare for the opening as much as you do! 

I recall Stiepan (I think that's how you say his name), the man who runs the Hanging Pawns YouTube channel, suggesting that whilst 2... h6 and g6 are both playable, he'd much prefer to play 2...g6 to avoid all of the complications. 

Kasparov played 2.Bg5 against a 2600 GM, and Kasparov was unable to find a win.

You would think, if 2.Bg5 was that powerful, then one of the greatest players of all time should be able to easily dominate a mid-level GM with it. But the Dutch held.

And I'm guessing, with "best" play, the Dutch likely holds against everything.

They do test games in the Top Chess Engine Championships, and occasionally they do engine matchups with limited opening books (where only move 1 is book, and every move after that is pure engine).

In the 1.d4 f5 games, the Dutch is usually a draw. Even at the top level, with titans like Leela at the wheel, black is still able to hold.

So I'm not convinced that there even exists a way to beat it. At best, white can put pressure on it, and hope that black makes a false step along the way ... (Though I suppose that could be said about most defenses.)

I heard the grob/grog cant be defeated either so at least they have that in common.

I dont know about bongcloud.