Dinesh D’Souza wasn’t allowed by the Judge to contest the selective prosecution of his case, so he basically had no defense and was forced to take a deal. The government agreed to drop the more serious charge if he’d plead guilty to the lesser charge, something he readily admits he did, however naive he was.
He does make the obvious point, though, that the Obama administration doesn’t seem to care about Harry Reid and his illegal use of campaign money, which only makes his point even more that he’s been targeted because of his political views.
He explains it more fully below: