My personal take - on the surface "cost cutting"; real answer "internal politics"
Dale (along with Rogers) opposed Jared Cohen and Sarah Robertson on their plan to repackage the MBS products, or maybe it was the specific method of repackaging, either way... After his exit interview and packing up his desk, he's talking to Emerson - he asks "who was it?... Robertson?" which clearly points to the internal politics.
Because he was about to embarrass his boss, the Chief Risk Management Officer, by uncovering intentionally obfuscated negligent trading activity that she was ostensibly in charge of overseeing and preventing.
I think it was just a regular down-sizing thing on the other hand it was a little bit weird with the USB hand-off but I dont think it was intended to be sketchy. That movie is a lot of fun, lots of good performances from Spacey, Jeremy Irons, and Zach Quinto.
There's a part in the the movie where a higher-up asks Will Emerson who all are left in his risk department after the layoff, and he points to his two junior analysts. So basically Eric Dale's entire department was cut.
Sam was constantly having "I told you so" moments with other executives, including the one who fired Eric, implying that they all had a good understanding of what they had been doing all along but willingly chose to ignore the risk. Laying off the risk team was the next natural progression of this, because they were no longer a real part of operations at the firm.
