Can I make all of humanity the enemy?

I mean obviously I can, but could I get the reader on board?

I'm writing a story where the main character is an alien who is colonizing Earth and in the process is taking human land, starting a fight. I plan to have the aliens win, but I don't want it to seem like a loss. How can I turn the reader against humanity?

 

Let's go Hollywood: WWII's ends differently and in the years thereafter aliens arrive to exterminate Nazis and their global empire—they rescue and relocate any lingering POWs, concentration camp prisoners, and slaves of the regime. New Earth belongs now to the aliens with good people existing in a sanctuary paradise enjoying their fantastic technology. Or something like that.

 

Anything can be turned into a monster if you dredge up enough things about it, even humanity. We have no lack of terrible things we as a collective have done. I would say start first not by immediately drawing the line of black and white but first paint both sides grey and focus of a few distinct aspects that serve to shade your aliens more on the light side and humanity on the darker side. Just don't go to extremes because then it starts to get a bit preachy.

 

If the alien the subject, not making it's personality too remote to empathise with will help. Subjective writing biases the reader to it's subject's point of view, even if that point of view is, say, immoral. Take any criminal/cop cat & mouse narrative from the criminal's point of view, people tend to root for the criminal. Do it from the cop's point of view and they tend to root for the cop.

Nabakov's Lolita plays a similar trick. It pits two monsters against each other, but biases the reader toward one such that, even though we know Humbert is a monster, Quilty seems somehow worse.

So I think that's a necessary but insufficient step toward what you're after already in the bag.

 

Well, everybody sympathizes with the underdog. Maybe don't make the aliens way too overpowered compared to people. There needs to be a struggle and maybe the humans almost win and in the process commit many atrocities. Maybe their military machine is corrupt and unfair. For example, the Romans used to beat their own soldiers like dogs for minor offenses like speaking out of turn. Maybe the human military in the frontier of space is able to get away with similar disciplinary tactics. Like how Vader choked his own officer. Maybe the humans do a Rape of Nanjing level atrocity against aliens. You can tone this down or up, whatever. The aliens need to seem sympathetic compared to the humans. Maybe the human species has failed to evolve at the same rate as their technology and the universe would be better off if they were to be replaced by aliens who are maybe more morally mature.

If you want a real life example of this kind of thing, think about the Britain occupation of India. So, probably this brings to mind negative connotations of Britain. Those aliens came and invaded India, and took them over. But think about all the barbaric practices Indians engaged in that Britain put to an end. For example, widows had to throw themselves on the pyre at their husbands funerals. To be honest, if we made the story of India and Britain fictional and changed the names, it would be really easy to make Britain look like the good guys and India look like the bad guys. Why do you think Britain invaded them in the first place? They thought they were doing the right thing. That's what you have to ask. How come this alien civilization is okay with their government engaging in this war to take over Earth? How about the politicians, the military, etc? What is the narrative that they tell themselves to justify their actions? And if you can answer that, all you have to do is tell that same story.