Anything that doesn't fit the leftist NPC narrative is labeled alt-right.
In our case, they hate us (alongside MGTOWs and Redpillers) because what we say goes against feminist agendas claiming women are oppressed, when in fact they are privileged.
They target Incels the most because we are more vulnerable than those two other groups, we are "weaker", more psychologically unstable (because of sexlessness), and of course, uglier than most people that belong in the Manosphere.
Ironically, it has been proved several times that women are bigger race supremacists than men (especially on those online surveys from dating preferences on apps and sites). Many racist white men would settle for an Asian or a Latina, but most white (and asian) women won't settle for less than a white Chad.