I don't see why everything published needs to be the absolute truth (which of course nothing can be).

If they had published six years ago, the whole community would have been able to validate and confirm in those six years, instead of just their own lab. Someone in a different lab might have had a better idea and the thing could be validated in two years instead of six.

As long as results are transparently and reproducibly shared, knowledge is knowledge and there's no reason to hide it.