What people don't seem to understand is that actors are human and have their own different personalities. They are NOT the character that they portray in dramaland or chungmoro. Digressing a bit here so bear with me...PBY is a reserved person who has gone through a lot of hardships to get where she is. She herself questions as to why she is considered full of aegyo and sees her nickname Bovely as somewhat burdensome. She seems like a true introvert who needs to recharge and have her alone time.
On the other hand Park Hyung-sik too has had his own fair share of hardships - called a psycho in his previous agency, practising alone with no friends, barely noticed in ZE:A. Nothing came easy for him. He had to start from the bottom rung to get where he is now. All through sheer perseverence and hardwork. He handles that fame differently. From all the BTS scenes he seems like a naturally 4D personality who has no problem being affectionate. There are instances where he goes out of his way to be nice to fans and people in general - calling back fans who couldn't take his autograph, putting his arm around that airport staff member. This is his natural personality.The only time he stops doing that is when he is in character as he is a method actor. His idol training just complemented his true personality. No amount of training could make a person like that. It's sad that people think of him as an idol package who is just nice to fans because he has to, which is definitely not the case.
I guess most fans wanted PBY to act similarly to her aegyo personality - which she didn't and it was pretty jarring to see PHS being his friendly self. Hence the comparisons and the idol training comments. Personally I feel that both actors' approaches should be respected for what they are without putting them in their own fanmade box which is quite burdensome. Lets hope that PHS doesn't let this get to him and stays his true friendly self.
P.S I can't wait to see him in a psychopath role. Hopefully UAA can get a movie role for him where he plays a killer or an emotional manipulator.