Because he look down MC origin and body shame him without looking into things properly. I got this far into the story only because of MC kindness that spread like wildfire even effecting me. Like, bruh! Mother fking btch! MC loved ML so much that even after reborn, he still save ML despite how ML tremple over him in his previous life. Though, the ML in present time was good, but to have the past b*tchY ML into the dog blood sht, like, oh man. I know it's for dog blood but I kinda don't want MC to show merch and kindness to this bit*h anymore. Can he just stop suffering please. I'm so irritated that I have to come and rant here before I think I can continue damn it.

MC is over his head with fear and ML his hatred to the world. As MC is stuck with his puppet emperor role and the ML just wanted to destroy the people that fcked his life up (not the MC btw). Unfortunately, ML never got to know the identity of the person who was once kind to him since his benefactor is too busy being scared... They are basically strangers in this first lifetime. So the potential good feelings that could have existed in the first lifetime is definitely zero. But their relationship had a turnover when MC was reborn and decided change both of their destiny. This time they properly fell inlove with each other.

that will act like a cornered rabid dog. Take note at he does not have the happy memories of the 18yo ML. There will be a brief imprisonment thing but nothing irreparable will really happen. Also I want to add that transmigrated ML may be cranky and had that murderer General personality but in front of the MC he merely becomes some gloomy tsundere.

To be specific, MC/shou is victimized by the villain and tried to run away from him in both lifetimes. While ML became what he is after becoming a s*ave and his only family died all caused by the clan of the same villain. Their only intersection is when they were young, MC treated ML with kindness for a bit before getting roped in the villain's manipulations.

the ML also gets reborn

If you read the tags/other reviews you'll know that ML later on reincarnates as well, losing all the memories of the current ML and that's where the divide comes in. He doesn't technically r*pe MC, LYM is willing and agreed to it, BUT it's a willingness that was under extreme coercion/pressure so that's some extremely dubious consent. I will say however, Ni Lie (the ML) in the past life never looked down on LYM for being inters*x specifically, he looked down on him for being the puppet of Sima Yu/the Sima family. They never actually interacted in the past life (as LYM and NL, even the first chapter had LYM kill himself before NL got there) and they were enemies in the past life to be fair. If I woke up with my fate changed by someone who used to be on the side of my enemies I too would be very apprehensive and skeptical. There's also a misunderstand because NL had found LYM's handkerchief on his body and the body of another official with no other context, thus thought LYM was seducing others (to which he legitimately was) for scheming.

Objectively, in both lives, the ML had it worse than the MC. The ML was basically dehumanised and treated worse than a f*cking animal. The ML who was only 10 year old at that time had his whole family executed, forced to be a s*ave, then become a plaything for the fourth prince where he was tortured and was forced to fight with wild animals. I just can't get over the scene where the MC had to treat the ML's wound that was crawling with maggots, and how the ML's was laying in his own feces in the f*cking cage. In the first life, the ML's sister was even forced to be a prostitute and was gangr*pe to death.

Sure the MC's life was also hard, but compare to the ML, we can see that ML had it worse.

The original Red Tiger King reincarnates roughly midway through the novel (around chapter 67 I think?) and then the ML and MC who have experienced two lives have to relearn how to love each other again

Yes, it's 100% HE. However if you're looking for bittersweet endings I'd still recommend it because the ending doesn't waste any time on fluff and the characters work so hard to get to where they are that the ending is completely satisfying.

s*upid original ML also came back and ruined everything. Just straight abuse by the ML who traumatized the poor MC.