I agree with this sentiment--but I don't think it actually contradicts the argument being made. Maps, stats, plot details, etc. are kept secret, so that they can be revealed.
		
		
	 
But, also so they can be changed on the fly.  A 'plot' goes sideways, you change it.  You don't tell the players who the bad guy is up front, not just because part of the point is to uncover who the bad guy is, but also because you just might want to change who it is based on how the story develops.  Secrecy keeps your options open.  In the end, you reveal who the bad guy is, even if it isn't the same one the notes behind the screen say it was meant to be.  Likewise, if your roll behind the screen, you reveal the result (hit/miss, save/fail, etc), even if it might not be the result the rules as written might imply.
	
		
	
	
		
		
			To me it depends in what way the fudging is being done. If I roll a stealth check, and the monster fails his perception check, but the DM decides that he still finds me then that sort of stuff pisses me off. That is cheating, because the DM made a perception roll and then ignored the result. It makes me feel like my stealth ability is useless, because regardless of how good my character is at stealth, the DM can randomly decide to render it useless.
		
		
	 
How would you feel if you declared that you were going to sneak past a monster and the DM just told you that you failed?  Would you feel like the ability was useful?  A 5e DM is entirely within his right to do that to you any time - technically every time.  
	
	
		
		
			If I see the DM reroll attack rolls for monsters, even though I know the monster has only one attack, then that is unacceptable fudging too.
		
		
	 
How do you know the monster only has one attack?  Maybe it has some n/encounter 'Action Surge' style ability?
	
	
		
		
			But I am not against fudging when the DM uses it as a tool to make the game more fun.
		
		
	 
That should be virtually the only reason the DM does anything... 
 
	
		
	
	
		
		
			And to me, an olympic level jumper should not be able to be tied by a chubby man with no training just because one rolled low and one rolled high, and the resulting number was the same.
		
		
	 
That's where the Empowered-DM ability to simply narrate results rather than roll papers over on hole in Bounded Accuracy.
	
		
	
	
		
		
			Barring a rule like resistance or melee damage being allowed to knock out instead of kill, damage always is.  The DM is not making a ruling if he is declaring an outcome uncertain, he is changing the rules.
		
		
	 
You can think of a ruling as a one-time rule-change if you like.  But, if it bothers you, you might want to thinking of it as a ruling, instead.  Either way, whether it's deciding to whether to roll or changing the results of a roll, it's something the DM can do, one of the many ways he's Empowered in 5e.
	
		
	
	
		
		
			The rules exist to say how the game is to be played.  That applies to player and DM alike.  The DM just has the authority to change, add or subtract rules if he wishes.  Those are house rules.  Outside of a house rule or ruling on something that is vague or the like, the DM has to follow the rules.
		
		
	 
That perfectly describes the attitude towards RAW & Rule 0 in the 3.5 era.   In 5e, the rules call for rulings to work at all, and the DM can make rulings notwisthstanding the rules without changing the underlying rules.  The Rule of RAW has been overthrown, M in DM is back to standing for Master.   ;P