Unbeknown Paedobaptist

"Master," said John, "we saw a man driving out demons in your name and we tried to stop him, because he is not one of us."
"Do not stop him," Jesus said, "for whoever is not against you is for you."

I came across these two verses today (Luke 9:49-50) and wondered what to make of them. It seems quite rebuking to me who can very often be very exclusivist and criticise people who do things in a slightly different way to what I would see as the ideal.
So, although we should avoid pluralism like the plague it's still a good idea not to go too far the other way and become extreme exclusivists... maybe?
You coul also argue for the Passion being good (i'm not i said you could) using that principle.
Just a random thought.