Speaking ahead of his defence of the RBC Canadian Open in Toronto, McIlroy reiterated his opposition to the divisive rebel tour, which will soon include major winners Bryson DeChambeau and Patrick Reed in its ranks with Dustin Johnson, Phil Mickelson and Graeme McDowell.
"I think we all know why everyone's playing in London this week," McIlroy said of the $25 million opening event at the Centurion Club, where just 48 players are chasing $4 million — the biggest first prize in the history of the game.
"It's boatloads of cash and it's money upfront and I get it. For some guys, that's really enticing. I totally get it, I do."
McIlroy still plays for appearance fees, but he admitted playing purely for money never works out well and he fears the 54-hole, no-cut format with players paid huge sums up front is not competitive golf.
"It just doesn’t add up,” McIlroy said, putting aside his concerns about the source of the money. "If I am a fan, I want to watch the most competitive golfers on the most competitive tour in the world and that’s the PGA tour so that’s where my hang-up is.”
On the players in London or about to join the new tour, he said: "I understand what their goals and their ambitions are in their life.
"I'm not, certainly not knocking anyone for going. It's their life, it's their decision, they can live it the way they want to.
"But for me I want to play on the PGA TOUR against the best players in the world. And I think for me, speaking to a few people yesterday and one of the comments was, anything, any decision that you make in your life that's purely for money usually doesn't end up going the right way. "
European Ryder Cup stars such as Lee Westwood, Ian Poulter, Sergio Garcia, Martin Kaymer and Graeme McDowell face possible bans from the DP World Tour and becoming ineligible to captain Europe.
But McIlroy believes all parties need to sit down and find a solution rather than just impose bans.
"Yes, still think they should be able to (participate in Ryder Cups)," he said. "They have been such a part of the Ryder Cup.
"I mean, look at the history that Poults has with the Ryder Cup. It would be such a shame for him not to be involved going forward, whether that's as a vice-captain or a captain or maybe one last time in a playing capacity.
"It's the same with G-Mac and a lot of these guys. It's hard because they're playing in defiance of the Tour and whatever else is going on, but I just think everyone just needs to get in the room and figure it out.
"I felt the professional game was on a nice trajectory where everything was becoming more cohesive, and now it's becoming more fractured again, and I don't think that's a good thing.”