I can't view the article but I agree that the rules should not get in the way of a good time.
That said, if the rules are getting in the way often enough to publish an article that explains why they should be ignored then perhaps the rules should be reconsidered.
Whats the purpose of having a large rules structure if having fun requires ignoring large portions of it?
That is hardly what he is saying - he's saying there will be a time and place in many games to ignore the rules, and the DM shouldn't feel it is wrong to do so. What circumstances that demand it will change from player to player and DM to DM, even shift based on setting, atmosphere, mood - any number of things.
He isn't putting out a list of flawed rules to ignore - he's saying that there are times when a judgement call can make the game more fun, because
no rule system can account for the
millions of different sessions of different campaigns being run by different players and different DMs.
In one fight, a group might smoke a climactic boss just a bit too quickly, so it might be acceptable to give them a final round to make the fight feel epic, rather than a disappointment.
In another, the boss might have a few too many hp, so it might be acceptable to have it keel over when the last person standing rolls that lucky 20 with the last attack they have left...
The same rule system can produce both situations. You can't fix both problems in the rules without enforcing that all players have identical characters who always roll the exact same dice in every situation. What you can do is encourage DMs to use their own judgement on what matters to the game they are running - the story, the cinematics, the challenge, the numbers, the triumphs, the defeats... every game has a different balance, and every DM will need to make their own calls.
All this article is saying is that they should feel free to do so, and focus on what is best for their game and their group, rather than adhere to some absolute principle that might reduce their enjoyment.
And I agree with him wholeheartedly.