You're absolutely right Willie, everything is easily avoidable in retrospect.
Thank-you, Luis.
I think if all these folks demanding perfection would stop to think about it, they'd realize that engineers understand there is no such thing as perfection. It is totally impossible to design a failproof piece of technology as complicated as the shuttle. That is the whole reason for providing "redundant" and "backup" systems whenever possible. If the primary system fails, hopefully the backup can help avert a catastrophe.
I can't name what backup systems were on the shuttle, but everybody knows there are many of them. Same thing on our naval ships, airplanes, etc. etc. etc. It all boils down to: it's not a perfect world. If it was, there'd be no need for backup systems at all.