That's how I feel about most conversions. There are a lot of great bikes being neutered for some ****ty fixie fad. In the end, you get a bike that's useless on hills, useless for long rides, and more often than not, useless for speed, since the wannabe who converted it thinks it looked cooler without brakes.
Have you seen the original derailleur for that bike?
it's a 3 speed that's as fragile as a fabergé egg, either it broke long ago and it's impossible to get a new one so this guy is making the best of it rather than scrapping the bike, or he's made it rideable without risking the value by keeping the derailleur on
or perhaps I'm completely wrong and it was fixed or ss to begin with like this one