Okie - It's apparent that you are thinking with a bit more calm now, but don't over-think your position too much or start to question whether you have a valid situation. I think it's pretty clear you do.
It really doesn't matter whether they actually attempted to call you on the radio or that these guys are pushing for faster, more production, or what. None of that is relevant. In every LOTO program I have been around the one hard-and-fast rule was NO LOCKOUT LOCK IS EVER REMOVED UNTIL EVERY POSSIBLE MEANS TO CONTACT THE OWNER IS EXHAUSTED. Some places simply do not ever allow this (as indicated by many previous posts in this thread) while others have written procedures that include manager sign-offs and records where attempted contact was made. In either case, it's the company's responsibility to document this procedure and when it's been followed. If no such documentation exists, they are in the wrong.
So, in most cases, a judge bases his final decision on what is the reasonable expectation. Assuming what you have told us here is basically the whole story, the reasonable expectation IMHO is that every attempt to get you to remove your lock WAS NOT attempted. If they tried to call you on the radio, they clearly believed you were available. If they didn't, they were negligent. If they didn't document their attempts, they were negligent. If their LOTO program doesn't include a procedure that details the steps to be taken and documented for such events, they were willfully negligent. In short, I don't see how any actions as you describe them put you at fault.
I don't believe you need to lighten-up or back-down. Everything you describe about foot-dragging, pressure for production, and so on have no importance with respect to this. A major safety violation was perpetrated by these guys against you and you did nothing wrong.
Don't start doubting yourself.