I'm not the person you refer to but I have my own employees so I'm qualified to answer this
Different personality types respond differently to different types of feedback. Some will be motived by criticism. Some will respond the way you want them to with o angry outbursts in limited quantities, aka. "putting a fire under someones backseat". Both of these can only happen in small amounts or you create a negative feedback loop where a player might start to think that everything he does is wrong, which severely affects motivation and confidence.
The vast majority of people respond to either calm constructive feedback - or my personal approach to all things management: Support.
Players who struggle tend to not struggle over something of their own making. They are well aware that they are not playing good enough. De Gea's role is a bit different than say Lingard because De Gea's role is fullfilled in split seconds where he either saves or he doesn't-. If he makes a mistake, no amount of yelling is going to teach De Gea that he can't make that mistake. He knows that. When you make mistakes you need (most of the time) positive reinforcement and a reason to be better. In this case Davids motivation is his teammates and his personal performance. Exceptions are cases like meeting the ball, attacking the ball on a corner, things lik that. But negative feedback on saves? That doesn't help anything.
In the example of Jesse Lingard: His role on the pitch is in a series of moments that can be recitfied with a good yelling because he has time to use the negative feedback to do something positive with it, chase a player, be aggreive on the ball, what have you.
The other aspect here is the dressingroom hairdryer: more often than not its used as a "Fire everyone up" tool when the performance just isn't there. Nothing more nothing less.
With regards to a press conference. Ask yourself this: What would be the purpose of Ole being negative? What does that achieve? The press conference is for you and for me. The ONLY reason for Ole to be negative from your point of view is fo you can feel valiation about being angry and justify that yelling at people is some how productive.
We had a manager here that took the negative route during press conferences, frequently singling out players for mistakes, blaming them publicly. I know that you can't imagine how stressful that is, but imagine your boss calling you out on live TV for a mistake you made and blame everything on your very public face. Then go out for a shopping trip after, wondering if any or how many of the people you pass by are thinking what a loser you are who can't even play a ball the right way. It's a team sport and somehow your contribution to your team and your teammates is SO BAD that the manager went out of his way to blame it all on you. Go to bed thinking about what mistakes you might make again, what chances you're never going to take again because you are lambasted in national media for not being good enough. That is exactly what happens when you call players out during press conferences. It achieves NOTHING. Sir Alex (almost*) never did. Ole (hopefully) never will. And thank god for that.
*Here is a link to an article about players that Sir Alex DID ciriticise either in public or media managed to sneak glimpses of private yellings:
https://www.manchestereveningnews.c...manchester-united-news-alex-ferguson-11918367
As Sir Alex himself said: Criticising a player in public damages morale. It achieves nothing.
We already know from the players themselves that Ole is more than happy to use his outdoor mountaintop voice behind closed doors. We also know from the players that Ole's strength lies in man management. Whatever Dea Gea responds positively to, I'm more than confident that that is being handled behind closed doors.
I don't really care if De Gea gets yelled at or treated to a spa weekend. Whatever gets him out of his head and back on the pitch is what I want. Not yelling because "players should be able to take it".
tl;dr: Public criticism is always bad and shows lack of character. Publicly supporting your players and geting behind them even when its a storm shows leadership. Don't yell at people for yellings sake, chances are you will achieve less than what you started out with.