I think brainwash isn't quite right a description. I think what you may mean is parents who who are very controlling about their faith. I've always tried to raise my kids with my faith (and that has changed too)...just as you described. I think the key is to always be open that other ways of thinking or being a Christian and they are just as valid and wonderful. Mainly the "only" people - can't use wine for communion, only wear dresses, only use the KJV, only homeschool, etc. etc. etc.
I think the key too is that there is no hard and fast rule to raising our kids to keep the faith. I wish there were.. really I do. I've seen too many kind, gentle Christian parents have their children turn away from the faith. It's just as heartbreaking.
The other thing out of our control is what other Christians say/do to our children. My kids are older and some of the things they've told me that Sunday school teachers or other Christian parents have told them will make your toes curl. My 23yr old dd went for about 3yrs to a small Christian school specifically for kids with LD. It was a great school and gave her the tools she needed to succeed in a traditional high school and in college. But, just last week dd told me that her teacher once told her that all girls should act dumb so they can catch a husband !!??! I was flabbergasted! OMG!! And she was telling this to girls will terrible self-esteem issues because they had learning problems!! What the was she thinking??
One piece of advice I got about 2yrs ago concerning parenting is to talk to God about your kids more than you talk to your kids about God.
So my advice from someone who isn't finished yet is to love your kids and pray for them.