It might be just how the Swiss system works. It tries to find the best player, but also eliminates the possibility that two players play each other twice. Riemsdijk was a bye in the first round (because pairing is by strength, and Riemsdijk is the strongest, this will always happen), then won from Starked in the second round (they were paired, because Starked was second strongest and won the 1st round as well), and then Starked won the third round as well, establishing that Starked is indeed the second strongest player, and Riemsdijk the strongest player in the tournament. Riemsdijk then won, because he defeated all other players who could have been a contender for the 1st place in the tournament.
I think you can do a similar kind of analysis for the first tournament you linked.
The Swiss system is meant to find the best players as efficiently as possible. With an odd number of players, it has to choose a bye that makes it least difficult to establish the winner, or in other words, those players where their ranking is least certain should play.
I’m still not entirely sure how the McMahon system works, but it might be worthwhile to use that system instead, see if it improves matters?