Yeah I notice that too with my wizard, learn ALL the spells. I am sure it is just a temp thing. Get the basic system for learning spells etc in the game then later on go through and select what/who can learn what spells/class. I admit i am not up to snuff with the 5e rules (I know all the other editions) BUT to cast a from a scroll that if not on your spell list/class etc one needed Use Magic Device skill to cast from a scroll (aka rogues casting from spells) but I do not know if that skill is in the 5e TT or it was changed to using the skill for said scroll (Arcane, Religion, Nature, Occult etc).