I can think of a rational reason that shouting (unnecessarily) should be socially unacceptable. Generally, it's either a sign of agression or is used to alert others to danger. In the case of agression the reason for its social unacceptability is obvious, however in terms of alerting others to danger, yelling unnecessarily and to excess in this context eventually causes complacency about it and can put the group at greater risk as they cease to heed the warnings.
Yeah, that is why in hindsight I tried to back off of that one but was too lazy to rewrite my post. You can also argue that using all caps is often used for emphasis, like boldface. It is a very rare instance when an entire paragraph needs emphasis.
Proper capitalization seems to be tricky. I may just start ending every post with "sorry i'm annoying and too lazy/innept to capitalize" which would be faster, especially with the advent of copy/paste. :).
I can think of a rational reason that shouting (unnecessarily) should be socially unacceptable. Generally, it's either a sign of agression or is used to alert others to danger. In the case of agression the reason for its social unacceptability is obvious, however in terms of alerting others to danger, yelling unnecessarily and to excess in this context eventually causes complacency about it and can put the group at greater risk as they cease to heed the warnings.