The story doesn't provide any context for this admission so there is no way to know whether this statement was freely given. There's no mention of a forensic exam.
Because of gendered assumptions about those who report having been raped (women lie, men don't) it's less likely that the investigators coerced this recantation. Even if they didn't pressure him to recant, real victims can decide to recant for various reasons so a recantation is not proof of anything. However, if there is clear contradictory evidence such as surveillance video which disproves the allegation then this man should be charged.
What's important about this story beyond whether the recantation is valid or not is that this story hasn't been picked up by those who focus on false rape allegations made by women. I have no doubt if the man in this case had been a woman that those men would have started buzzing about this case. I might have found an anonymous comment in my moderation queue with a link and a snarky remark about women's lack of honesty.
Looking at the comments of this story (I suggest you don't unless you are ready for lots of bigotry) the version I read was an update from the original story. Some of the commenters to the original report were quick to make rape jokes about the original allegation or to call the report "buyer's remorse." But the feeling I get from those is that this is a form of gay bashing where gay men's honesty is equated with their assumptions about women's honesty. Because the original story said this didn't appear to be a hate crime, some men responded with racist and gay bashing remarks.
It isn't until comment #63 that a commenter references the change in the story. From that point on the gay bashing dominates.
Now that I've highlighted this case 1 or more of those men who run sites claiming to highlight all the reports of false allegations may feel obligated to post about this case to prove that they are not gender bigots. We'll see.