Not what I have read..
From my own understanding, Sony is not using a DDoS attack, but instead they are attempting to poison the torrents that have been leaked.
The way this appears to work is that the (AWS) servers join the torrent swarm and advertise themselves as seeds. They then pass garbage to the peers instead of legitimate chunks. Of course the peers then also start spreading the garbage as well.
In order for the peer to recognise that the chunk is a fake, they must download the entire chunk and verify it's hash - by which time it is too late and the partial garbage chunk is already being spread farther. I haven't verified this, but some BT clients apparently do not verify the hash of each chunk compounding the problem even more.
Whilst not actually a DDoS, the principal is similar to the layman - the effect is to flood the swarm with irrelevant data thus making legitimate transfers a lucky dip slowing or stopping the torrent in its tracks.
To be honest, I can't see why anyone would be aggrieved with Sony for these tactics - it does not affect torrent sites and is specifically targeted at stopping the transfer of data which was stolen from Sony (I use the word stolen in this case as the malware used attempted to erase the data from Sony's network)