I can't agree, unless:
1) using your foot for the pull-the-chair move is flagrant
2) using a foot-hook to prevent the rebound is flagrant
3) holding position with one foot against a jump-shooter is flagrant (Bruce Bowen)
Are we talking about the same play?
I have to disagree with your three "unless's" listed above. Or at least the two that I understand:
1. When a player invokes the pull the chair out move, his feet are firmly planted to the ground. While the offensive player shifts his weight toward the defender to back him down, the defender simply moves out of the way and the offensive player's momentum carries him to the ground and ultimately a traveling turnover. This is not a trip in the least. The defender doesn't sweep his foot in to the offensive players leg/foot to trip him. Often times there is zero contact, which is primarily why the move works; i.e. the offensive player goes to sit down (make his move) and the chair (defender) isn't there. This is not even remotely close to Dantay's blatent trip.
2. This is about position and leverage. The rebounder angles his body with his feet/legs and puts them between the opponent and the basket. This is a simple physical position and leverage ploy that is utilized on just about every possession within the course of a basketball game. There is no leg sweep here to trip or dislodge a player. It's a basketball related play through and through as physical position is a fundamental key in the game.
3. Not sure I'm understanding what you mean on this one, so I won't comment.
I can't understand how when a player falls to the ground and then purposefully sweeps his leg to trip an opponent anyone would disagree that is a cheap and flagrant foul. It would be one thing in the game of soccer, where your feet are your primary tool and slide tackling is part of the game. There is some gray area in that sport since your feet are your primary tool. It's the opposite in basketball, you're only allowed to use your hands to touch the ball and defenders. No gray area here.
On the "pull the chair," in addition to moving out of the way, you lodge one foot right behind the foot the player is balancing with. He can't move the foot backward, so therefore, in addition to being off-balance, he can't re-plant the foot to re-balance himself. In other words, he's got no choice...he's going down.
On the second, you're right that it is about leverage, but it's about leverage to get underneath a player. If the player jumps forward, he's coming down groin-on-hip. Works well at preventing people from jumping over your back. Very Barkley-esque way of holding rebounding position.
For the third, the idea is to leave a foot between the feet of a jumpshooter. When he comes down, he's immediately blocked out....if he drifts forward, he'll be pushing you in the back with no ability to move you (no leverage). Very Bowen-like, although he's more aiming for getting under foot rather than blocking out.
Every one of these plays hurt opponents who try to out-physical you. I think they're part of smart basketball...and infinitely better enforcement as a defender than falling down and waiting on the referees to call a flop. Dirty? To some extent, yes, but again, a part of smart basketball, in that a player trying to play a reasonably clean game isn't going to get hit by them. And if you're playing to out-physical me, in my eyes, you deserved what you got.
You push me, and I grab/trip/impede you. I throw an elbow on a drive, and you mistakenly catch my head. You try to body me on the perimeter, and you take a forearm. There's a certain amount of self-enforcement that goes on in any game.
