This whole situation is so hard to read. Now there are really many persons who spoke out and it gets harder to determine which one is legit and which one is not. That said all participants have individual views, emotions. reminiscences on the whole thing.
Someone can completely forget a bad thing he said about someone else a year later, whilte the other can be damaged for years. The bad thing mentioned could have been put out of context or misunderstood or taken for something way bigger than it was and was meant to be.
F.E. "You look not good today" can be interpreted by the recipient as "You are ugly" "You wear ugly clothes" etc.
It could have just meant: "You don't look healthy today". Or "Your clothes don't suit you well."
Furthermore they were all very young teenagers. There is a shot timespan when the brain of adolescent reorganizes itself. Oftenly this takes 3-6 months and people behave irrational and not like before in this phase. They are worse at remembering and learning than before and their hormones control their behaviour stronger in this phase. This often takes place between the 7th and 8th or 9th class.
So we should not hold the adults responsible for every bad action they did while growing up, We got youth custody because adolescents are not as responsible for their deeds as are adults. That said there are many bad actions that simpy should not occur even in such states.
The way Soojin presents herself to her fans, her group and her company seems to be entirely different from some cases mentioned. She now does not seem to be a bully who would hurt others just for her own fun and amusement and to feel superior.
About the past Soojin only a few can really judge because the most weren't there.