The Religious

Matthew 3:1-12
Why does John call the religious people a "brood of vipers"? Why does he tell them to "bear fruit worthy of repentance"?
In Luke's gospel John's message of repentance is directed to everyone who comes to him. But Matthew notes that John specifically targeted the religious with this message. Why?
I mean it makes sense to tell "sinners" to repent. Prostitutes, tax-collectors (who in that society were really traitors to their country and God), gang members, pagans, atheists, liars, cheaters, adulterers and people like that need to change. But John directs his message to the religious.

Could it be that we, the religious, need to repent of:

• Using religion as a cover up for our own sin. Instead of examining ourselves we simply see the wickedness of those who are not part of our religious group.
• Using religion as a way to get power. We tell people that in order to be faithful to God they must submit to the religious organization. This can be blatant or very subtle, like using guilt to get volunteers to run programs.
• Using religion to keep God at a distance. Instead of getting to know God we make spirituality about obeying a list of rules.

Could it be that being religious actually makes it more difficult to experience God's grace?