Came across an interesting video that mentions that due to the nature of Korean music companies there is significant distortion in the public media when discussing kpop artists due to investors attempting to increase the value of their investments (or in some cases decrease the value of a competitor), rather than fans.
I'm sure that's the case. The only question is to what extent are investors doing this, relative to true fans? If they have a lot of money invested they would probably be willing to spend on bot farms, and other related things.
Recent events have shown that kpop stock prices can fluctuate predictably based only on rumours, so I would not be surprised if many people are trying to abuse this by planting false rumours (both positive and negative), and bulk-buying to inflate sales numbers. (how many of these Chinese bulk-buying groups are actually run by active investors?)
This would generally be illegal, but it's very hard to prove and I have heard of no one convicted for it.