Is Cowboy/Biker/Millennial Church Biblical?

Question:  Is it Biblical to plant new churches that are geared toward a specific audience?  (i.e. cowboys, bikers, millennials, etc.)

This is a question I wrestle with in my own mind.  I don't know of anyone who would say we shouldn't be trying to evangelize specific groups of people.  (For instance, our church has a faithful group of men that have a wonderful ministry in the biker community.)  But is such outreach more properly done through a ministry of an existing church, or by the contemporary method of planting a new church specifically for that group of people?  Jonathan Leeman, in his book Reverberation, has this to say on the topic:
"The church of Christ is to be united around the gospel words of Christ, not around ethnicity, socioeconomic class, age, style, or anything else . . . Consider carefully, therefore, what it means when we deliberately attempt to unite people to our church, not around the gospel Word, but around some point of natural affinity.  Whether we mean to or not, we're sending the message that (1) the gospel Word is not sufficient for creating unity among sinners; and that (2) other forms of natural unity are just as worthy as gospel unity . . . trying to unite or attract people to my church through some point of natural affinity or gifting means I'm potentially relying on the power of people's idols to build my church."
Ouch.  What are your thoughts?  Agree or disagree?