
Taekyung (same) wanted to find Heejae (uke) and make him fall in love with him to break his heart. The thing is however, Taekyung didn't know Heejae lost his memory and he thought Heejae left him and dumped him. Taekyung didn't follow through with breaking Heejaes heart because he fell in love with him again, and he felt especially bad when he learned Heejae lost his memories of him.

His actions sped up the process. Taekyung's family company wanted to take the whole family down, Taekyung was in charge of making sure that Heejae goes down in that scheme. I believe that he was the one that was involved in the embezzlement thing and came to Heejae pretending to be a side character to the whole plot in order to hurt him emotionally.
Am i forgeting something? What did the seme do so bad to the uke that everyone is hating him for, aside from the company thing wich is obviously early planed and out of his hands. He lied to him at first but he didnt take any "revenge" and fell for him again. I feel like i forgot something since everyone is bitching so much like hes the scum of the earth