[Cthulhu_]

They really aren't if they can't take criticism and feedback on board, or can't see how their code is objectively bad.

Senior is just a job title / pay grade, it does not mean someone is a good developer. Thankfully I've never had a label like junior/medior/senior attached to me, because while I have plenty of experience I don't think the job descriptions for senior developers applies to me. Probably impostor syndrome but still.