I'm not convinced that it should be 'whom'. It's a sentence fragment. It's not a subject or an object of a sentence. Replacing 'who' with 'he' or 'him' makes no sense either way.

And lastly: It's not a novel or paper. It's just a quick phrase used artistically. With 'whom' is sounds stuffy and out of place. 'Who' sounds correct in the context, and hits the target audience.