Isn't there some sort of advantage rule for those types of infringements? If it's cynical and intentional, shouldn't they be getting carded?
Often it's worth taking a yellow card to stop the attack, and often you can foul for advantages that are small enough to get away with. Especially in the first 20 minutes, because there's an unwritten rule that you can foul harder and get away with it early on. You can also get a yellow for "persistent fouling", but it's rarely done, and when it is it's generally in the second half and the manager can respond by bringing the backup fouler on as a substitute.
Sometimes the entire team gets in on it; Brazil noticeably took turns to hack James Rodriguez in last year's WC quarter-final, although this then backfired when Colombia responded by assaulting Neymar and effectively ending Brazil's tournament. Another notable backfire is when a particular brutal RM-Barca Champion's League semi-final was decided when
Messi dribbled past four booked RM players to score a crucial second goal. Notice how Pepe, the teams de facto fouling DM, holds his hands up and lets Messi go when bringing him down would have stopped the goal, demonstrating the value of replacing your fouler when he gets booked.
Nowadays the trick to avoiding a booking is to foul as early in the opposition move as possible. If you do it when they're about to score you get sent off, and if you do it when they're breaking into space you get a yellow, but if you do it
as soon as your team loses the ball, you invariably get nothing. The best and most unscrupulous managers (i.e. Mourinho) have long since realised this, but most fans, pundits, and referees haven't caught on.