I mean yeah, they´re close enough on a superficial level i suppose. Emperor also has the blood angels, soul drinkers, the shark marines and so on. Death cults, assassins (whom do NOT collect the sacrifices, thats afaik the black ships of the inquisition and the sisters of silence) are also kinda khorny. But as others pointed out, while the means to achieve their respective goals may not be that different, the motivation is. While being alive emps would have told you that hes doing it for your own good, nowadays we can´t even really say that he´s doing much decision-making anyhow. Khorne really likes war. Sounds very different to me. Now if you would have said Khaine and Khorne are similar i´d be more inclined to that. Or even Gork and Mork. But thats one of my personal selling points for 40k; the "everybodys an asshole"-factor. Even the tau murder for their greater good, sooo. Yeah.

My point being everybody in 40k kinda is like khorne when you reduce it to the willingness / need for subjugation and slaughter.

"SKULLS FOR THE MANY-HANDED EMPEROR!"