Merkley's reputation for getting along with teammates and coachability problems (ie. having the same issues since he was 16, with several different teams and coaches) may have been more widely known (coming into the OHL as a 1st overall pick), but if you followed the OHL, DeAngelo's reputation was significantly worse in terms of the kind of person he is.
On HF now the main difference is based on DeAngelo's tweets/political views, on top of the detractors he has, he also has a weird niche of new super fans who pump his tires and downplay the reputation he's had from junior to the NHL, even rewriting the history of his issues in the Rangers organization. It's quite strange, really.
Miller was less known because it's the USHL, but uh, if you read any threads of his and compared it to Merkley's, Miller's reputation is waaaaaay worse.