Masterwork Tool for UMD?

[Mastikator]

A book entitled "How to Win Friends and Influence Magic Items".

I was never able to wrap my brain around the concept that a particularly charismatic rogue could figure out how to use a magical item or scroll that a dedicated Wizard (when casting divine stuff) or Cleric (when casting arcane stuff) was incapable of using or how said rogue could trick a magic item, that will not work for certain races/genders/classes/alignments, into working for them.

Same question could be asked on why sorcerers base their magic on charisma.