How many? 1/10 of 1%?
If MU was legitimate, you can be sure these figures would not be hidden, and would be instead the #1 bulletin point of their defense. Instead, DotKim is now claiming a conspiracy theory.
MU made more profits than DropBox had revenue. Take away those accounts that signed up (tricked into) to download illegal content, and what do you have left?
Never MegaUpload specifically.
To better illustrate the problem with your devil's advocate approach ask yourself the same question adding in the words in brackets: would you permit a person (wrongly) accused of being a pick pocket to use (his) funds (incorrectly assumed to come) from stolen wallets to pay for his defense?
The Feds freeze the assets of a fraudster, e.g. Bernie Madoff, when accused of a crime. They are not yet proven guilty, no, but there is a pragmaticism that underlies the decision to trade defendant rights for the public good.
Per the document linked to Madoff's estate was put under an "order freezing assets" [1]. Dotcom's property is described as being "seized and restrained" [2], not confiscated or forfeited.
[1] http://www.sec.gov/news/press/2008/2008-293-order.pdf
[2] http://www.nzherald.co.nz/technology/news/article.cfm?c_id=5...