What armor restrictions?

I've been studying the LBB's lately, which has caused considerable lengthening of my D&D things-I-thought-I-knew list. One of those things is the prohibition against magic-users wearing armor. This seems to be the only passage in Men & Magic on the matter:

The whole plethora of enchanted items lies at the magic-users [sic] beck and call, save the arms and armor of the fighters (see, however, Elves); Magic-Users may arm themselves with daggers only.

To my eyes, this is only talking about magical armor. It's possible that there's a later passage in the LBB's that explicitly bans mundane armor for magic-users, but based on this I think they should be able to suit-up in full plate. Even the daggers-only clause is joined by a semi-colon to the clause about enchanted items, so it may imply "with enchanted daggers only." That could mean that they can use all mundane weapons but no magical weapons except for daggers. If the referee was feeling perverse, he could even interpret it to mean that magic-users can't wield any mundane or magic weapons except for enchanted daggers. I assume that the accepted doctrine against armored magic-users is rooted in how things worked at Gary's gaming table, but I haven't found much discussion on the usual forums about what a literal reading of the text would mean. Your thoughts?