2 things:
First thing, what Bob has done wasn't nice, but if you have followed closely you probably have more cloaks than before. For example when he first posted that he wanted to sell large amount of cloaks and we were still above 220 ksats...

Second thing, when you have large quantities of btc and you want to achieve profits you can do 2 things, you either baghold and hope for the best -- e.g. those who bought drk above 0.02 drk/btc and are still waiting -- or you can try pump and dump on some level, depending on scale of your investment and your total available btc amount, like Bob has done, and will probably do in the future as well. I understand it although don't like it. There is a third way which usually doesn't work out -- slowly sell, and hope that the market will survive till you are finished -- so it's either case 1 or 2.

Buy high, sell low! Peace!