Brood of Vipers

Matthew 3:7-10(NKJV)

But when he saw many of the Pharisees and Sadducees coming to his baptism, he said to them, “Brood of vipers! Who warned you to flee from the wrath to come? 

Therefore bear fruits worthy of repentance, 

and do not think to say to yourselves, ‘We have Abraham as our father.’ For I say to you that God is able to raise up children to Abraham from these stones. 

And even now the ax is laid to the root of the trees. Therefore every tree which does not bear good fruit is cut down and thrown into the fire. 

Why do you think John said that?  He's being pretty judgmental isn't he?  It almost seems like he is going to refuse to baptize them. 

I think the key sentence there is "bear fruits worthy of repentance".  Did John perhaps think that they were seeking his baptism merely for show?  That they weren't really sincere?  That is the way it seems to me.