I have strong opinions about this... but if I may, I present an important issue here in question form.
Lady Gaga says a lot of beautiful things. In her concerts she talks about love, a lot, and I think she talks about it in very genuine ways to her. If you took many of these words out of this context, out of the weird hats and very strange shoes, and put these words into a suit and tie situation in front of pews... they would very often sound quite spiritual.
So, Question 1: Does every word she says have to be spiritual for any of them to spiritual? And is this true for would be preachers too?
And, Question 2: Sure, she does not use the name of God in her sharing. So does this make her "for us because she is not against us"? (Mark 9.38-40). Or is she a "wolf in sheep's clothing"? (Matthew 7.15-20).
OK, so I picked one secular artist. And you could limit this thought to just Lady Gaga, or... looking at the two scripture references above, think of the issue in much broader terms.