There's a difference between being content in something and being content with something. If I'm homeless of unemployed or in debt, should I be "content" with that, or work to make changes?Only to those who idolize marriage. The right attitude is, either single or married, be content in every circumstance.
And in 1 Corinthians 7, Paul says that if you're not content with being single, then maybe it's better to marry. Paul does say that he, personally, is content with being single, and that he wishes that everyone was like him. But he also says that not everyone's like that, and says that he's not commanding singleness.