There’s a lot but people like to forget because it’s too scary to think while idolizing their idols.
The one’s most people are familiar with are so called slave contracts which tries to take as much profit advantage and control over idols. And we know how JYJ was banished from Korean entertainment after splitting off TVXQ.
There have been too many to count instances of kpop companies sexualizing idols, both male and female. Sometimes even when they are underage. No surprise both BSH and MHJ have been involved to a certain degree. This was often common in nugu groups like Stellar but once sexy concepts became unpopular it died down somewhat.
The dark side of kpop. Every once in a while incidents of abuse, SA, and corruption come to light. Psychological abuse seems to be the norm in kpop companies, especially involving criticism on appearance and weight. Physical abuse isn’t uncommon either. Fans know of several incidents but are typically kept quiet “for the good of the group”. We know that in many instances when fans complain of mistreatment it’s mostly a facade for them complaining about lack of satisfaction among fans rather than for the well being of idols.
There’s a long list of criminal or immoral occurrences or practices in kpop. From tax evasion, death threats, racism, scams, etc. but due to NDAs and lack of empathy and fear of retaliation very few come to light.