Replying to A Hypothesis concerning screamo

We've all heard the earsplitting tones that are 'screamo', but do we ever wonder? Wonder why scream? Why start screaming now? Music has been around for a long time (234124 years?) but only now have artists resorted simply to screaming as a means of communicating their emotions rather than through heartfelt, expressive lyrics. Dont get me wrong, some bands can scream and I am ok with it. By some I pretty much mean Thursday and the occasional glasjaw song. So, is screamo simply a result of an incapable lyricist with insatiable inner-conflict or what it seems?