Some might view that as blasphemy. Just taking the name of God in vain.
Why? Clearly the lyrics were referring to the actual personage of Jesus, because they then reference a crucifixion- it's not using it as profanity. Also, technically Christ, which is what is actually used in the song, is a title meaning "anointed one", not a name- technically.

And I'm not sure why it'd be blasphemy per say.
I realize that some people may not like anything that refers to God or Jesus in a way that isn't explicitly praising them, but, you know, with all due respect, tough.

Christians almost all maintain that Jesus was a historical personage (In addition to being religiously significant), so it's perfectly valid for people to reference him as such.
Actually, saying "you know how hard [life] can be" and referencing a crucifixion is in a sense expressing a defacto agreement with part of the Christian narrative. The fact that Lennon was later shot and killed at a young age because he was famous sort of lends the song extra credibility.
Of course, he was comparing himself to Christ on what sound like equal terms, and rock musician does not equal messiah, and I'm aware that the Beatles were given crap for joking in an interview that they were bigger than Jesus because their albums had sold more copies than bibles had sold over a certain time period, but these are rock musicians, not candidates for the Papacy.
I mean, part of the thing with secular bands performing songs that reference religion is that they probably aren't going to sound like hymns.

It's just people, writing and performing songs that happen to reference Christianity in the same way that the songs might happen to reference women or money. It'd be really odd to hear a secular rock band do a song about the details of the Nicene Creed or something.

Although, the Mr. Mister song I posted towards the beginning of the thread is using part of the liturgy, *in Greek*- "Kyrie Elasion", which I've always thought was rather impressive.