He allowed extra-judicial torture practices there against UNHR and any humanitarian objections. He didn’t do what Trump is going to, but he allowed it to normalize and continue despite the power to stop it, and makes it less of a leap for a right wing freak to make something like this happen. It’s not a “thanks Obama”, but people down voting holding Obama to account for keeping it open want Dems to be blameless despite complicity in the neoliberal bullshit dating back to Clinton as the party swung for corporate interests and abandoned their humanity.