Not castling while playing Dragon/English attack against Najdorf

I have recently encountered many high level player (2000+) who decide not to castle in many occasion in sicillian dragon or English attack, where as black you go for queenside attack, and as white you go for kingside attack, but the problem arises when the opponent decides not to castle which in fact renders my attack useless and gives free opportunity for my opponent to attack my queenside with rook and double bishop. Even going for kingside, players usually slide their king, and attacking the kingside becomes pointless. So my question is how do I reply such players, I know it's definitely not a correct thing to do in long term but how do one punish this sneaky tactic which seem to be common all players I have played?

The general chess wisdom says: don't castle as long as it's not really necessary.

My point is if not castling was really ideal thing to do then why top level grandmasters don't go for such lines? There must be some downside of such play, but how would you exploit it?

Leaving the king in the center for a long time is a totally standard strategy in the Najdorf lines where White goes 0-0-0. Delaying 0-0 is more controversial and unusual in the Dragon. Tringov - Szabo, Lugano Olympiad 1968 is an instructive early example of what White can do.

In the Najdorf, it's pretty common for Black to delay or completely forego castling.  If you haven't found grandmaster games where this is done, you need to look harder. A standard premise of the Najdorf is that Black's king is often safer in the center.

It's much less common in the Dragon, but it's occasionally seen there too.

Often this is easier to discuss with particular lines in view.  Are there any games you want to show?

Castling is almost always safer. It is generally much easier to attack a king left in the center. Castling also adds power to a counterattack, as it connects the rooks.

In general, yes.  But not necessarily in the Najdorf.

If Black is not castling in the Najdorf or Dragon I'd say the most obvious answer is to try and open things up in the center, usually by playing f4 at some point. That way you either trade your f-pawn for opponents e-pawn or possibly push the pawn to f5. Either way you eventually end up with an open f- file for a possible attack. He'd probably be forced to castle at that point since f7 is vulnerable otherwise. 

Many times you can sacrifice pawns and even minor peices to crush open white's center and counter-attack the king.

This is one of the sample game in which I won and opponent decides not to castle at all. If not for opponent blunders, he would have pushed king forward and bring another rook into play.

#7
Also in the Najdorf castling is often better. Famous example
https://www.chessgames.com/perl/chessgame?gid=1008390