Well it's no less of a questionable tradition than some others (and I won't start with the questionable stuff done in the US

), but it has it's place.
And it's probably one of the most misunderstood traditions. If you run with the bulls, you are supposed to run
with the bulls. Standing in the way or isolating a bull from the herd so that it gets frightened (and thus more aggressive) is actually to be avoided. You are supposed to run with the bulls a certain route as a kind of "rite of passage", even though the event has lost part of this meaning.
This goes especially to those badmouthing this: Don't judge what you don't understand. I'm not a big fan of this tradition either, but I won't judge it in this way while in my country there are traditions like butcher/slaughter fest (feast of freshly slaughtered animals to celebrate the harvest), the punchfests (mass brawls) on labor day or the battues in spring and autumn, which people from other countries probably can't relate to.
Just food for thought.