They did, because a lot of the flesh sacrificed was their food, and they were forbidden to eat blood, therefore they bled it out. All kosher meat is treated that way, right up to now, firmly. And Gentile Christians ought to be a little more careful also:
"But that we write unto themthe Gentile believers, that they abstain from pollutions of idols, and from fornication, and from things strangled, and from blood" (Acts 15:20 AV).
Do you not see that if Jesus' Body had not been bled dry through the heart pumping blood out of the strain-enlarged spike perforations in his extremities, combined with final exsanguination of his abdominal cavity and heart, that His Body, if filled with blood, would have been the same as a strangled animal, which without the incision of a major blood vessel, the blood would have no escape path?
But that obviously was not the case for Jesus.
And as an aside, the posture of there having been a long time before He was pierced cannot be right. He gave up the ghost at three P. M. and since it was the preparation, all activity had to cease by six P.M., the sunset, the beginning of a double Sabbath. So the disciples had only less than three hours to get his body down, wrap it up, and bury it, with the women washing it and applying spices. The piercing had to take place before all of this, which does not give much time for the blood to gel and cause rigor mortis (if it was to occur at all, and I do not believe it could).
My Friend, you don't have much wiggle room, considering all the facts, for your theory to be accepted. There is another factor of taking into account the Holiness of His Blood that needs to be dealt with, but it cannot be that his Blood stopped being fluid and life-bearing at any point. So His Blood would continue to drain at all times, until there was none left.
Commentators are not always right, and many times they disagree with each other. They are not to be totally relied upon. Always check them out.
Give me a few days... but I did the research and this is a Gnosticism, if you really believe Jesus was not resurrected in the same body in which He was crucified.