I mean Vegapunk, what do you expect the Roger Pirates to do? Heck you yourself can only give this information on your death, and you expect them to give the information when the government can easily cover this up as well as most people wouldn't listen or believe them just because their pirates.
Also it reminds of what Rayleigh said to Robin. Even if she knew of the void history at that time, there would be nothing she could do about it as things were then.
All in all great chapter, but man Vegapunk really does make little sense at times.