And yet, it got you to look at it. You figured you were the one out of 10 people who'd consider it, and therefore buyers would be scarce and you'd be more likely to get a good deal. But there are probably more than 10% of CL watchers of the same mindset, maybe enough to get even more potential buyers than a fully informative ad!
So is the seller just lazy and ignorant, or actually being clever by appearing lazy and ignorant.. you never know. Could be someone who doesn't know what they have. Could be someone wanting to just "get it gone" with as little effort as possible. Could be a divorce situation where the woman wants to sell her ex's bike for $50 out of spite!
Out of the ignorant looking ads that have a price on them, there is a whole continuum from deranged high price to screaming good deal. I got about "half off" my last bike by clicking an ad that was pretty much just: model, year, price. After learning the approximate condition, mileage, and title status I told the guy he was asking way too little money, but he stayed true to the ad.