I guess they thought Malcolm Turnbull's policy agenda was just far too likely to be well-received for the modern Liberal Party to take on board. Turnbull has all these crazy ideas about republics and reconciliation and signing Kyoto and failing to hate on brown people. It's Just Not On. Not what liberalism's About. Just ask Miranda Devine. I'm not saying Nelson is a right-wing maniac - I don't think he is - but his election as Liberal leader, with the support of the Liberal right faction, is a clear sign that the Liberals have no intention of learning from their mistakes.
As a matter of fact, the Libs have gone insane. Contrary to current conservative wishful thinking, this election was about more than a repudiation of John Howard, the man; witness Turnbull's results in Wentworth and Petro Georgiou's in Kooyong versus the debacle in, say, Bennelong or Lindsay. Hard right doesn't work; moderate liberalism does. It's what people want. But to admit as much would be to take on much of Rudd's centrist agenda, thus, in the view of some Libs, depriving the party of its raison d'etre. I get that, but turning right just for the sake of opposition isn't going to get them elected. It'll just turn them into a bigger version of the NSW Libs. And then there's Tony Abbott's dark warning that he might challenge for the leadership at a later date. For a Howard man, he doesn't seem to place much stock in leadership stability.
Serious questions about the future of the opposition aside, though, this existential crisis they're going through is highly entertaining, wets vs. dries vs. crazy uglies; my personal favourite moment was when Tony Abbott declared (with, one pictures, a hand over his heart): "I always regarded myself as the honorary president of the John Howard fan club." Aww. True believers can be so cute sometimes.