The same libgen which is illegal in the US and whose sources include those obtained by Aaron Swarz? That libgen?
What matters is how you got it. Accepting a watch someone freely offers you is different from breaking into a house to steal it, even if the watch you were given turns out to be stolen.
Yes. This isn't even controversial. Aaron broke into a network to obtain papers. The CFAA is applied when someone breaks into a network. Downloading from libgen isn't breaking into a network.