Finn probably could get rid of him but he didn't want to try. He also didn't want to let go.

"I-... I felt alone on Vaikuntha. I missed you and Rey so much. I think that-" That it made him weaker, more prone to the darkness in a frail attempt to protect what wasn't there. But that also felt like it was putting part of the blame on Poe and that wasn't fair.

"Being here with you helps a lot more than you could possibly know. If I do try to push you away, it isn't because I want you gone. I just want to keep you safe, that's all... But I'll try to keep you close, too."