I’m sure many took an interest in Cho bet he rejected them.
Yes, a number of students have said they tried to reach out to Cho but it was he who rejected them. Maybe he was scary in some classes, but others described him as just quiet and withdrawn.
My daughter had a Korean girl in her class in grade school who was very shy and would not talk to anyone and wanted to be by herself. She is attending an Ivy league college, apparently doing well.