If you have actually worked at Tumblr, or another social company that has to deal with blocking accounts, and can provide some analysis of what goes into these decisions (is it automated? How many people are involved? How much discretion is given to individual employees? What are the legal implications if Tumblr did nothing?) that would be interesting and informative.
If Tumblr doesn't want bad publicity over it then they should tell people why their accounts are being closed.
They can't be bothered, so it's left to rumor and speculation.
it makes me wonder: if you're actively doing research on these modern day areas of conflict and the culture that's in them, would you rather ask for forgiveness or permission when posting your material to a site that monitors material of that nature? and if it was so easy to gain forgiveness, what would stop people from framing said areas of conflict in different lights under the guise of research?
though I agree, tumblr isn't exactly my first thought. :P
'I assume he has been suspended because Tumblr thinks Chris is spreading jihadi propaganda'
Which would be Tumblr doing the exact opposite of what you say they do.