There’s nothing inherently wrong with having a conflict of interest. It happens all the time, and the key issue is disclosure and how you manage it.
Sometimes it is perfectly fine for the conflict of interest to exist, provided there is disclosure to the relevant parties. However, accusing someone of having a conflict of interest after they have determined that they don’t is a surefire way to spark a reaction. No one likes to have their integrity questioned, but sometimes people are blinded to their conflicts as they pursue self-interest.