Here’s the official/canon explanation for his behavior from the novelization (although I know most here don’t care for that):
Poe stepped into the hold from the cockpit. His face was haggard, but he seemed as determined as ever. He’d been so serious lately, often on the verge of anger ever since Crait. He felt responsible for the decimation of Resistance, Rey knew. She understood what that was like, and braced herself. She wasn’t going to blame him one bit for laying into her; she was just going to take it.
So the impression I’m getting is that he was angry at himself and taking it out on others - and droids were prime targets.