Pardon the bump, but since it needs to be addressed...
The alt-right is largely a manifestation of frustration with the liberalism of Obama's America, combined with a rejection of Bush-era notions of conservatism. This basically leads to alt-right positions being a grab bag of contrarian bullshit and second-option bias. A lot of it is also a desperate attempt at articulating a right wing position without sounding like evangelical neocons ("Fuck you, dad! Jesus is a kike on a stick and Hitler did nothing wrong!").
For people who claim to not give a fuck what liberals think, a great deal of alt-right discourse is about signaling to liberals how smart and different and edgy they are. This is why you really find no creationists or fundie protestants in the alt-right. Instead they're into "HBD," which is mostly rehashed 19th century "race science," but they think that having IQ stats and cranial charts at least looks more intellectual than believing that Adam and Eve rode dinosaurs. Alt-right ideas have a heavy air of "survival of the fittest" and "might is right" (the latter actually being the name of an incoherent 19th century tract that a lot of alt-rightists suggest).
You're on the right track, but it's still not quite encapsulating who they are.
It's difficult to say who coined the term (some say Paul Gottfried), but Richard Spencer played an instrumental role popularizing the term with his former website Alternative Right. Much like Occupy Wall Street, the alt-right is a loose coalition of disparate elements with radically different belief systems. You can have LaVeyan Satanists, white ethnonationalists, Christian fundamentalists a la Common Filth (despite his attacks on the alt-right, he's still followed by a good number of them), Traditionalist Catholics, Eastern Orthodox converts, neomonarchists, neoreactionaries, various elements of the manosphere, European Neopagans and all other similarly minded people claiming to be alt-right.
The common denominators are:
1. Anti-globalism. Funny since progressives were the champions of the anti-globalization movement in the '90s and early/mid '00s. Now, the tables have turned.
2. Anti-status quo.
3. Anti-egalitarianism. If anything divides the left and right sharper, it's the question of equality, and the alt-right sees it as a cancer.
4. Anti-political correctness.
Only a small minority of the alt-right consists of bonafide Fascists or National Socialists, and they are often savagely attacked and ridiculed (as "14/88" types) by other alt-righters. Conversely, Fascists hate the alt-right, particularly because they feel that, unlike Fascism, the alt-right has no systematic framework from which to govern:
http://ropeculture.org/2015/12/28/why-the-alt-right-is-gay/
http://ropeculture.org/2016/05/06/anti-intellectualism/
http://ropeculture.org/2017/01/13/zero-tolerance/
The white ethnonationalists within the alt right can largely be seen as a predictable reaction against the feminist gender "identity politics" and anti-white ethno-nationalist groupthink that have been promoted by neoliberals and their progressive lackeys for the better half of the 20th century.
It's hardly a mystery why the alt-right gained the traction they have since everyone else is aggressively promoting their own narrow ethno-nationalist or gender group interests, white heterosexual males alone are singled out and criticized whenever they start belatedly defending their own group interests. Of course, societal elites have been busily promoting their own political and economic interests all along, increasingly behind a pseudo-humanitarian globalist and multiculturalist veneer, but are doing so mainly at the expense of the American working and middle classes.