While the WCA is not a democracy, the people that lead the WCA are still obligated to the community upon which they rely. They cannot just do what they want.
To be honest, I can't believe people are so worked up about this; the solve is clearly illegitimate. If it isn't just a prank (and I feel things have been taken way too far for this to be a prank) then the solution is simple: put the burden of the proof on the competitor. The reason for this is that the evidence is overwhelmingly against this solve being legitimate.
The situation would then parallel very well with the case of Matyas Kuti when there was overwhelming evidence that his solves were illegitimate. If this competitor cannot provide good evidence that his solve was legitimate, just as Matyas Kuti couldn't defend his "bld" methods, then this solve should be DNFed and a penalty should be applied to the competitor. Of course the history behind the two cases is different, and as such any consequences would be different, but that is up to the WCA board to decide.