Read the novel
Any spoilers?
The major spoiler I can give the story was never about BDSM. The story is written from Lee Seodan's POVs. Team Leader has been trying to push him away many times, but Lee Seodan was the one who choose to come back to him. Lee Seodan will also be the one suggested they continued with BDSM while he keep reiterating and emphasizing to think through it carefully.
Their relationship has always been a two way street. People unable to see this because they fail to understand it was Lee Seodan who chose this for himself. They both understand he's not normal in the bed. Lee Seodan understand the risk he's taking and actually set up the tone for their relationship.
Does the author even know what bdsm truly is?
Turns out she only made an abusive relationship with unhealthy power dynamics and put a dticker of bdsm over it.