That's right. I ride all of my bikes in the rain, and not one of them has rusted like that. And by riding in the rain I mean commuting, so when I get to the office I'm not going to dry it, and it remains outside, uncovered. And when I get home, it gets parked in a covered garage, but I'm not going to wash it dry it daily, in fact, I don't wash them at all during rain season.
To me it seems like that bike was ridden on salty roads and/or sat for long periods of time under the rain.
+1 on this and the CLP post.
I do not have a garage to put either one of my scoots in - and they've BOTH seen action in the rain. The CLP will help a lot with all the various fittings and metal bits once you get the surface rust off. Never-Dull (comes in a can) is pretty good for REMOVING the rust, although you may need to use chrome polish or even a bronze or copper brush/wadding on some of the more stubborn pieces. Once un-corroded, the CLP will help keep it that way.
I'm TOLD that Windex is one of the better things out there to clean chrome with - once it's cooled down.
When I don't have time to thoroughly clean the bike after being ridden in the rain, I use a fresh water rinse, and an inexpensive leaf blower that I use only for blowing off the bike. My wife calls it the "Harley Hairdryer" and I can have the bike rinsed and dried off in a few minutes.
If you're one of those people who HAVE to buy expensive baubles for your "baby" - Harley makes a small hand held blower that they'll be happy to sell you for about $60.
You don't have to keep your bike in a hermetically sealed, climate controlled environment, and only take it out on sunny, low humidity, non dusty days to keep it in pretty good shape.