Morkus from Orkus
If you are going to make that claim, you will need to back it up. I already quoted the 1e PHB as telling us that they can wear armor. I'll quote it again since you have now both ignored it, and then cut it out of your quotes.Quoting the 1E PHB "... but they do suffer somewhat from their inability to wear protective armour of metal.." also "... druids are unable to use any armour or shields other than leather armour and wooden shields.."
Then bring in the training rules, which ramped up the cost of training for play not pertaining to the class. It did more than just 'block their magical abilities'.
"...unable to use any armor or shields other than leather armor and wooden shields (metallic armor spoils their magical powers)."
Do you see the bolded and now underlined portion? I hope so. That portion means that druids can in fact, and it is a fact, put on metal armor. Otherwise druids would be completely unaware that it affects their casting AND Gygax would not have bothered to tell players that it did so. That warning means that druids can put on metal armor, but it keeps them from casting and using their abilities.
Further, there's not one roleplaying reason given for why druids would be unable to wear metal armor, other than the loss of their magical powers.
I have backed up my claim. Can you back yours up?