I think Jason was occasionally reckless, but whether he was truly self-destructive or not, it doesn't make Bruce any less responsible to me.
Of course, by the stage Jason was more angry than happy as Robin, it was already too late for Bruce to do much of anything about it. None of the Robins have reacted well to being benched; Dick ran away from Wayne Manor more than once in just that circumstance, and Steph... He must have feared that taking Robin from Jason would only alienate him further and would only fuel his rage further - and this time it would include Bruce as well. Which seems likely to me, and not advisable at all.
So they were... kinda stuck. And very very very doomed, but that's one of the reasons why I luv them.
I feel I shoudl clarify: none of the above is intended to relieve Bruce of the guilt of Jason's death, but I think that Bruce is more guilty of the situation that made Jason's death 'inevitable' than of his death itself. Being Robin didn't help Jason's psyche at all. And Bruce is entirely responsible for that.
And I now just totally buy Bruce being a completely stubborn mule when he faces situations that remind him of that. I believe in the Scary Bat Ship of Silent Self-Flagellation and Vehement Stubbornness. I do, I do.