CrossFit: Not Even Once
I was not even the slightest bit surprised.
I've done the exact same thing. Four years ago I blew out my back trying to deadlift 445lbs with bad form. I did it again two weeks later because I thought my back had more or less healed- but it had not. And then I blew it out again in about September of the same year, though that time was not nearly as bad as my back had strengthened in the meantime.
Eventually I learned my lesson and started concentrating on form and careful lifting. While my deadlift form on heavier weights is still ugly, I've also learned to dial back the weights so that I don't kill my back every time I lift heavy. Nowadays I deadlift in the 425lb range on heavy days, with solid form.
That way of thinking, however, is almost alien to CrossFit. It is very rare that you will find a CrossFit coach who actually knows what he is doing, who insists on people taking breaks between sets, and who understands that you can either lift light weights for high reps, or lift heavy weights for low reps, but not lift heavy weights for high reps.
CrossFit deserves every last bit of the bad press that it gets, in my opinion. I will always advocate for people getting strong and healthy through the transformative power of the cold steel barbell- but I do not want to see people hurting themselves in the process. And a "sport" that considers pain and suffering to be selling points is never going to be one that I will approve of.