I'll be honest, I don't really know those coaches personally, so I won't be able to confirm how they truly are. All I know is, and it's a fairly proven theory, that yelling is not a good management approach. Yes, it works in the army, where there's really no choice, and yes, it tends to have great results in the short term as fear is a great motivator.
However, in the long run, is a proven recipe for failure. People cannot live in a constant fear, they will find ways to escape. In the nba world, that means tuning out coaches.
The only way to lead a group of difficult personalities over a long period of time is to earn their respect with your knowledge and skills, not by instilling fear in the people you manage. What needs to happen is for players to work hard not because they are afraid of you, but because they want to return the trust.
and of course, you seem to equate somebody who respects players and tries to adapt to their unique personalities (like triano does) with softness, which is strange to say the least. I think it's not at all unreasonable to expect an environment where there are hard rules that everybody must obey, while maintaining a civilized level in player-coach relations using pg-13 language and mature approaches to solving issues.