Xanor

i'm not a person who comment a lot but people need to understand that you only see 1h of a 24h day, that they are probably not used to be in this type of show where you can get a lot of attention from multiple people and so your feeling can be confused easily,
Some are getting a lot of hate comment because of that i really don't understand (the couple that you are shiping since the first scene that you see from them will not automaticaly work) ,

For Si an is just confused by having attention from multiple men and want to make a good choice and don't want hurting them as you can see her reaction she has after the clear decision she made about Theo by not going futher than that

For Jeongsu i think a lot of people hate him because after few days of the show during a game were he didn't really know everybody, he decide to not choose Sian to get to know other women (+ he goes to se Si an after to explain himself) he now have make his choice after seeing the date with Youjin , yes it took a long time but i don't think he played or anything

The major point here is the fact that Sian didn't go to Jeongsu to talk about that, and that totally logical because they are at the begining of the show and it would be really strange if she goes and just say "Hey choose me next time, i'm upset, don't go to other womens" and so she talk with her ego and decided to choose an other man too, which bring misunderstandings

For junseo (probably the one that i like the less), he don't really talk about his feeling so we can't blame him for this it's totally normal for some people but could have listen more to Sian and try to change his way to talk, but you don't change people this easily.

people are too much invested understand that you hate real people, even if it's stage or whatever there's real hate comment on social media of the cast
That's my opinion you are free to not agree with it

(sorry for my horrible english tried my best but not used to write this much in a different language)