IDs are good and healthy for the game. Those who dislike them are not interested in a tournament finding the best players. (I concede that some people are instead interested in playing in a tournament to play in a tournament. IDs are not good for those people.) There is a whole slew of discussion on this, and it boils down to being a mathematical fact as long as matches are two games, and tournament standings are directly tied to how many games you've won. Change to a one-game match, or a best-of-three match, and you'll still see IDs, just less of them.
I can say a lot more, but really don't want to bring up old arguments into this thread. You cannot make IDs illegal. If for some moral reason you're opposed to IDs (there's no logical reason to be opposed to them.) then the way to prevent them is to change the tournament structure. And even then, they won't go away entirely, because they're mathematically sound at most Swiss tournament brackets. (Single Elim, obviously, they don't work with.)
(That's the end of the actual post. Following is digression about IDs and Swiss math.)
So, the reason we have a Cut instead of straight Swiss is that it's possible to drop a game but still win the tournament. A straight Swiss continues until you have an undisputed best player, which is usually when you either have only one X-0, or multiple X-1's who have all played each other so that you have a direct ranking for them.
Double Elimination cut means you can drop two games and win the tournament.
Basically a lot of this gets screwed up because you're supposed to only play against people who have an identical record as you going into the round. But, in Netrunner, each game counts for tournament points as if it were a full match in other games, and you play two games against an opponent before pairings are re-posted. This means that after one game, you have half the field as 1-0 and the other half as 0-1, in a sense of tournament points. BUT, we don't repair! This means we have the entire tournament of 1-0's playing 0-1's, which breaks Swiss pairing rules. This is why it gets really weird for Netrunner, where after the first round, instead of having a known quantity of X-0 and X-1, the number is unknown. (0-4 X-0's possible, and zero to eight X-1's possible.)
So, the reason we have IDs is because they sort of restore Swiss logic to the pairings. If in the final round of Swiss, I'm playing against someone with the same record as me, and in the standings, there are X or less players within two game-wins away from my points going into the round, where X is the Cut number, I am guaranteed a spot. If there are X or less players within one game-win from my points going into the round, I'm highly favored for a spot; it depends on tiebreakers for those who are within a game-win from me. (If I ID and they sweep, we end at same game-wins.) The reason this restores Swiss logic is that you're playing against someone in the same position as you, and at the end, you both have 'played a game' against someone with an identical record without changing the positions of the Swiss rankings.
I was lazy and only looked at Absotively's third link. You can see from Swiss that 5 people have 18 points. We can't see results or pairings, but we can guess that four of those people were paired for the final round of Swiss at 15 points. (I think Netrunner's currently using 3 points for game win, anyway...) This means that those four could ID the last round of an 8-person cut. It also means that two of them could safely ID the last round of a 4-person cut. No one could ID the last round of a 2-person cut, but importantly: Only those four people could win the tournament. No one else can get the points and SoS required to make it into a 2-person cut. Heinzel specifically couldn't have made a 2-person cut, yet he took Second in the tournament. This is why we don't do a 2-person cut.
Heinzel and Mirilu swapped positions, and this is why we don't do a 4-person cut.
A 16-person cut for a 27 player tournament doesn't make sense. The only remaining one we can do is an 8-person cut. We cut out some 15-point players, 'randomly' (based on SoS, but SoS isn't as strong an indicator as game-wins.), to give them a chance to win. Even though, in this case, we see that it didn't make a difference, except #2 and #5 swapped places.
We use Swiss and then Double Elim cut to give the largest illusion of possibly winning the tournament for as long as possible to the players. Swiss also has the side benefit of allowing people who cannot possibly win the tournament to continue to play until the Cut, at least. IDs are a natural feature of this tournament structure because the Cut always comes before the number of Swiss rounds we would need to get an indisputable winner. (Normally it takes too many Swiss rounds to find this out, but for Netrunner it's doubly true because of how a match is structured. There's no guarantee we ever get a mathematically indisputable winner with Swiss pairings until it becomes Round Robin pairings.)