From what I have read, these quilts will be subjected to industrial type washers and dryers. That could be why they are concerned about the monofilament thread. Maybe it doesn't hold up to the high dryer temp.
Don't feel bad, I have done things like that too. You know what you are doing and you jump in cause you are anxious to start and your eyes just skim right over one or two little words. Don't beat yourself up over it. I will bet there is another charity like a homeless shelter or domestic abuse shelter that deals with little ones that would love to have it.