When and where did shandies first become popular and why do they get such a bad reputation? I was recently at a local craft beer festival and I tried a few shandies (my favorite was Time Traveler) and now I'm starting to get into them as well. But I've heard mixed things about their history. Some people say it goes back hundreds of years and others say it's a much more recent phenomenon. 

With that said, why do they have such a bad reputation? They always seem to score low on beeradvocate and ratebeer. To me it seems as though people are rating them as beers rather than what they actually are, shandies.
From what I understand, Shandies as we see them now are more similar to the German Radler.  Radler means cyclist in German.  The way I understand the story is that a small pub owner was besieged one day by a slew of thirsty cyclists and knew that his beer supply wouldn't hold out, so he cut it by mixing it with some sort of lemon drink he had on hand.  As far as I know this origin story isn't confirmed and Radler likely grew out of folk attempts to "sessionize" and extend the supply of leftover lager through the summer when lower alcohol and more refreshing drinks were wanted.  According to wikipedia the first printed mention of Radler as a drink was in 1912: Lena Christ: Erinnerungen einer Überflüssigen - Kapitel 20. I believe contemporary Radlers use a lemon-soda sort of drink that's more like a carbonated lemonade than what we'd think of as soda.

Shandy itself is short for Shandygaff which is a British English term from the mid-1800s referring to beer cut with ginger beer or ginger ale. In fact, the OED still defines it as such while Mariam-Webster has loosened it up and allows for any non-alcoholic drink to be used in place of ginger.

As to their reputation, if you'll forgive me a little supposition, most commercial shandies are very pale duplications of mixing lemonade (or lemon soda) with a beer yourself.  The first commercial example I saw was Lienenkugel's and it was abusively sweet.  Sam Adams and The Traveler have fared a little better, but I think a major problem is that to commercially produce a shandy you need to heavily filter and pasteurize the beer and lemonade  to make sure the sugar doesn't ferment or use a non-fermentable sugar, which would change the taste from fresh beer and fresh lemonade.  At the scale a lot of breweries operate at, it possible some of them aren't even using real lemonade regardless of sugar type.  Also, while continuously popular in Europe, beer cocktails never caught on or were lost in America and we tend to think of them now as marketing gimmicks by macro-brewers (Bud Light Lime, Bud Chelada, Miller Chill), though as they become more visible, I think they'll become more accepted.

That said, fresh shandy is incredible, I like using wheat beer.