It wouldn't hurt for them to ask a schoolmate to church or to join the Boy Scouts but, they need not be in the hallways with a blow horn.
Peer pressure works both ways.
Needless to say, (and I'll repeat as necessary) ignoring the problem will not make it go away, it will only fester.Those *other* children are also our future.
Repeat as often as you like. My kids have been in public school. I have served on the PTA board and as an ADDitions volunteer. Sparing my kids from 12 years of brain-washing and preparing them to be world changers while befriending the many government schooled kids we encounter in our many outside activities is, in my opinion, a better way to contribute to the good of this nation and a superior way to prepare my kids for life.
I did not always think this way. I happily put my kids into one of the best elementary schools in the area. I still have friendships with some of the staff there. I believed it was important for them to be around a lot of different kinds of people and to be a good influence on the kids there who needed that good influence. Unfortunately, their learning needs were not met well and I got tired of my daughter coming home and lecturing me on the latest environmental issue (You're wasting water, Mom! Don't let it run while you're changing a diaper!) or freaking out because she was afraid she was going to get AIDS (do we really have to warn them in second grade?) While the teachers hated losing them, they supported our decision. That same daughter went on to get her teaching degree and taught one year in a low performing public school. She will tell you there was no positive peer pressure there and she will be homeschooling her kids. She will also tell you that it is not for everyone and you should do what works for your family.
On the other hand, I will say that the only way to break the strangle hold that government has on education in this country is to starve them out. If homeschooling is possible for you and you wouldn't hate it, give it a try! Deprive them of your presence and your money. Force them into market solutions for education so that the government does not have the opportunity to indoctrinate all those "other' kids and parents have choices beyond the public school to which they are assigned. The public school system is socialist by nature - you don't have a choice in where your child attends, who your child must associate with, who teaches your child and what your child is taught. By participating in the system, you are affirming it.
But, of course, if you are happy with your school and your kids are thriving - leave them there! Homeschooling is not for everyone.