In any case, what the WHAT?

   Not that it affects me in any way, but why do people say it is rude to use upper case to communicate on the internet?  It is the same as shouting, they attest.  I agree that unwarranted loud speech can be jarring, and hard on the ears.  But, really, is reading slightly larger script an assault on the senses in any way?  "Ouch, those bigger letters hurt my eyes.  How rude!"  I think it likely that back in the infancy of computer-ese, someone for some reason objected to reading something written in all caps, and so the mantra began. The seed  of nuance was sown.  I mean, of all the stuff that's posted on the internet, stuff that could rise far above the level of rudeness, it seems likely that writing in block letters would not even make the list.