Cramer: 'Coal doesn't complain' — United CEO may be longing for his old railroad job

United CEO Oscar Munoz isn't used to dealing with customer complaints, CNBC's Jim Cramer said Wednesday.

As a former president of CSX, a railroad transportation company, Munoz is used to dealing with trains and coal, not people, Cramer said.

"I think what's not talked about enough is what Oscar's background is. I'm not being facetious in that coal doesn't complain. He was from CSX. He's a railroad guy," Cramer said on "Squawk on the Street."

Cramer's comment came after the CEO said in an ABC interview Wednesday that the violent eviction of a passenger from a United flight "will never happen again."

A video of Sunday's confrontation, in which a passenger was dragged off an overbooked United Express flight, sparked outrage on social media and some calling for a boycott.

Munoz at first supported the action. Later, he apologized "for having to re-accommodate these customers." On Tuesday, he issued a detailed apology.

"Oscar comes from a different environment, where he was trying to get labor relations better and this is one where he backed his people," Cramer said.