Yes, the fact that 3 million people were deported during Obama's presidency is correct according to the Department of Homeland Security (DHS) Yearbook of Immigration Statistics.
But the contention that most deportees were not given a chance to plead their case in court can be different. Although expediting removals were applied against border crossers and certain types of criminals, most deportations still included the legal process. Issues like poor legal representation and language barriers in immigration courts, highlighted by the Migration Policy Institute (source), cloud the character of the justice system.
Therefore, although the statistics on deportations are correct, more information is needed on the problems with the court system.