I think your only madness is in calling Justin Bieber an artist.
We can be influenced by this world and the powers that live in it or we can turn our backs completely on it and live each day for Christ.
I will tell you something my freind, you will fail.
Only Christ can live the life of Christ, the rest of us just try our best to mimic it.
We are convicted by everything we say see and do in this world Christian or not, the only difference is grace, brought at a mighty cost. you or I did not pay a penny for.
In your statement above and with all love I have to ask why you felt it was ok to use the word "Crap" how did you justify what you obviously assumed as an innocent enough word to use?
So if someone listens to popular music they do the same thing, to them its innocent enough, but just like you felt it was ok to say "Crap" but unacceptable to say the "S" word, I feel its ok to listen some music and not others.
For example I use rapcore aggressive music in my powerlifting to induce more adrenaline for a lift if my energy levels are low. (I could care less about what the idiot is saying even if I could make it out, all I care about is the drive)
Personally I dont go out of my way to Listen to a song that celebrates death, satan or the hate of Christ, and in the same way nor would I put poisoned food in my mouth or wear a shirt with anti-Christ slogans on it.
These are those planks Jesus mentions hanging out of our own eyes.
Nothing, no work is acceptable and even our best works are like filthy rags remember, You say Crap and I listen to thrash metal when I lift, both are unacceptable, but both are covered by grace.
Life is in the Word.
Philippians 2:12
12 Therefore, my dear friends, as you have always obeyed—not only in my presence, but now much more in my absence—continue to work out your salvation with fear and trembling,