Bradley Manning
didn't dump everything. His most famous leak, the 250,000 diplomatic cables, were not simply released.
According to Wikipedia, at first Wikileaks itself released just a couple of cables. Next, it partnered with some news outlets to select specific cables to leak (with redactions to prevent harm to individuals). They released 220 cables at first, and a few thousand more later. Granted, the whole set of 250,000 were fully accessible to specific journalists, but it's not at all the same as a "data dump".
Some months later, a boneheaded journalist published the actual password for decrypting the original cables; later, a backup of the encrypted cables somehow became available as a torrent, so the full set of cables could be decrypted. But this was unintentional and of course, neither of these mistakes was made by Manning himself.
I myself question the wisdom of Manning's release of these cables (I respect him mainly for leaking the Collateral Murder video) but the idea that he "dumped everything" is plainly false.