It's a play on the name of the site. Mt. Gox -> MtG: OX
Its name was originally an initialism of Magic: The Gathering Online Exchange when it was an exchange for Magic: The Gathering playing cards.
Mtgox.com really did start off as "magic the gathering online exchange", and was a site where people could buy/sell Magic cards.
Nerds being nerds, the guy who ran the site got into Bitcoin when it first came out, because Bitcoin is interesting to nerds.
After Bitcoin got big, Mtgox became "just bitcoins", and was eventually purchased by the company now running it.
I wonder if dylz still refers to LG as 'Lucky Goldstar'?
So while it was named LG because of the initials of Lucky Goldstar, its name is still just LG (or I guess "LG Corporation").
Security was an afterthought - which might have been okay on a niche hobby site but wasn't when real money started to be traded.
When they get their act together and the issue stops coming up every six months it won't be as relevant. Until then, slam away - it gives potential users something real to find when searching for info about a service.