Wikileaks-related terms did not really trend almost at all last week. The only related trend today that currently trends in a few countries is the much less popular #imwikileaks! Pretty suspicious. If this is real censorship, it is much more profoundly unacceptable than just deleting someone's account, because it's not like trying to block that one account, that one voice, but like censoring and manipulating the collective voice.
Now, I'd probably could give them the benefit of the doubt, but seeing how Twitter suspended their own scheduled server maintenance last year in order to not interrupt its users from tweeting on Iran's protests, for me, this is a good indication about how one-sided, and political, their motivations could be in nature. If Twitter indeed censored Wikileaks from trending, then this is akin to have tried to manipulate public opinion by enabling/disabling the right bits each time, as they see fit, and then serving the result back to us, as something that traditionally was considered "democratically popular". And who knows how many times this could have happened in the past.
Like Digg.com, Twitter became what it is today because it made its users believe that they're part of an internet force that embodied democracy on the way information is becoming popular. Therefore, Twitter has no real excuse if it's censoring trends, because it's like going against its own roots. I hope that Twitter comes clean and explains the situation. One thing is for sure though, trends were not representative of the Twitter community this past week. Not by a long shot.