I'll give you an intelligent response.

Here's the thing. You're right. Gillard wasn't voted in by the people as PM. But technically, no PM has been voted in by the people as PM. Did you fill out a ballot with the question "Who do you want as PM?", because I sure didn't.

She was, however, voted into Federal office by the people of the Division of Lalor. She was then designated as leader of the Labor Party by her own party, after a leadership spill. Now, except for one point in post-war Australian history, the leader of the political party or coalition who holds the majority in the House Of Representatives is designated the role of Prime Minister.

In regards to the last election, Gillard and Labor of course made deals with the Greens and Independents to put herself in power, but in truth, this is no more immoral than the the deals and concessions made between the Liberal and National parties. In fact, these arrangements could be considered a sort of informal, temporary coalition. These kinds of deals are actually made quite frequently in other countries (for example, in the UK currently), but are virtually unheard of in Australia because of the traditional two-party system.

PMs who were "never voted in by the people" by your definition (i.e, were never the designated leader at election time, and never won a majority Government) come from all sides from politics, and include Billy McMahon, John McEwen, Frank Forde, Arthur Fadden, and Sir Earle Page. Many others later won elections after becoming PM by being designated the leader of the majority party, including Paul Keating, Malcolm Fraser, Harold Holt, Ben Chifley, John Curtin and Robert Menzies.

Hope this helps.