The Alt-Right consists of people on the political right who have formed their own movement, separate from the cuckservative Republican establishment. It is basically defined by white identitarian race-realist groups, like white nationalists, white supremacists, and neo-nazis. Some Alt-Right figures, such as Richard Spencer, Roger Devlin, Gregory Conte, and Andrew Anglin see the incel movement as potentially useful to their own type of pro-natalist agenda. There aren't many pro-natalist movements out there, so the alt-right kinda hogs the most prominent spot. Any other pro-natalist movement would also likely be sympathetic to incels. You can basically tell how alt-right someone is by how much they use the word 'cuck'.
The Incel Question
here is Grotesque's response
It's because most of them denounced us at first, in a lame effort to find a common ground and seem more moderate with their enemies. Because teehee nobody cares about the ugly guy standing in the corner.
Then, they realized that incel numbers are growing quickly and there's shekels to be made. Thus, they are throwing their hat in to be the guy that "helped" us, and become a de facto spokesmen for incels.