Dear 100 Hour Board,
Why are togas and loincloths socially unacceptable attire? They're definitely more comfortable than pants.
The short answer is because this isn't Ancient Greece or Rome. The long answer has to do with changing social norms, underlying culture, prevailing attitudes about fashion and modesty, and availability of resources, but I'm not enough of a sociologist, psychologist, or economist to really give a full explanation of why all of those things changed. You may just have to content yourself with knowing that because we live in neither Ancient Greece nor Ancient Rome, the way we live our lives is quite different from the way they lived their lives in a lot of ways. And if that means we don't get the comfort of togas, at least it also means our society doesn't encourage slavery as the spoils of war, and I'm pretty okay with that.
Anciently togas were only to be worn by Roman citizens, and foreigners and slaves were forbidden from wearing them1. Are you a Roman citizen? If you aren't a land owning Roman citizen then not only is it it socially unacceptable, but illegal under ancient Roman law.
While togas are strictly off limits, there are still places that wear loincloths. I was hesitant to do too much Google searching for reasons that should be obvious, so I didn't find anywhere specific for you. Wikipedia did say that there are native tribes in the Amazon Rain forest that still wear loincloths. So if you really want to wear a loincloth all you have to do is find a place where it is socially acceptable. As you may have noticed, the USA is not one of those places.
Togas and loincloths are only socially unacceptable because not enough people wear them. If they're as comfortable as you say they are, you should have no trouble finding a band of people to wear togas and loincloths, convert a celebrity to your cause, get a photo shoot, convince all of America that they should be wearing them as well, and make America the new Ancient Greece!
-guppy of doom
Are you telling me this is why I get so many strange looks when I go out in public?
~Anathema, needing to seriously rethink her wardrobe