Did you really read the stroy?? They left them because the enemies knew who they were and their identity, that's why Candy can't even go back to his work because it was the enemy's desire for the two of them not be involved anymore. If they stayed with Shadow and Uno, it would cause a bigger problem than it already has. Candy even mentioned that "We're not safe here because they already know our faces" so they must stay at the base or hotel or whatever they were in "until eveything is settled" something along those lines. Why are people hating on them when it's basically their story??
Regarding Shadow and Uno, it was their choice to help Candy. Candy pushed Uno away multiple times and making it clear that he doesn't need a partner nor will he like him because he was never into men until Hajun. Plus it's their job to support Candy because they were a team and Candy is the one heading that mission. Uno even created the plan and they all talked about on how to deal with Hajun being kidnapped so don't you think it's mutual even by force. They can make their own decision but still helped Candy, Uno even stated it's not their reponsibility on what happens to Hajun because that's his choice yet he still helped Candy because he couldn't resist his love for him. How's that Candy's fault??
Yes, i don't. They are kinda selfish. Which is not really wrong hence kinda. All they think is about themselves or their lover. Like the world around them doesn't matter. First normal people were killed bcz they were mistaken for them but they shown no remorse(again not really their fault, but normally people would feel immense guild if they are the reason for someones death, even if a little)
Second they have no care for Shadow and Uno, of course they can fend for themselves. They have their own reason to fight but still they put themselves in danger to save the ML, yet the mc left them behind and ran away to have sex with his lover. Seriously? Atleast use first aid before having sex, it's like they only think from their dick.