Sure, ok. But this is a little like saying "they said we couldn't break the speed of sound, but we did. Now they say we can't break the speed of light, so they could be wrong". The airplanes we have now are mostly possible because of the enormous increases in power output that we've been able to apply to the problem (and in the case of some gliders, improvements in design and materials)
A few points:
this is not a disappointment, it's a marvel of engineering and human output
but even so, this particular design isn't a first step to a practical human powered helicopter. This is not me being a pessimist, it's just an analysis of the design.
The guy in the bicycle seat here was putting out 1HP on average, which is a LOT, for one minute. I'm a dedicated cyclist, I can put out, say, 250 watts for long periods of time, that's 1/3 as much power. Most people who don't do what I do (i.e. ride a few hundred miles/week) can't come close to that. So maybe we're talking 1/6 HP.
Forget the human powered part for a minute - is it possible to design a helicopter of any type, that can lift 200-ish pounds with a 1/6 HP engine? We're talking about an underpowered weedeater engine or an electric drill motor.
Propelling people forwards is easy which is why bicycles are fun and efficient. Propelling people upwards is extremely hard and I don't think there is a practical means of making a human powered helicopter that would be useful for much more than stunts like these.