Why don't the cheerleaders and anyone else who wants to participate just set up right outside the football field and continue to hold up the banners. Supposedly, the law says that this type of activity cannot happen on the field, but they can continue on the school grounds. I would look for a way to just stay within the law and continue. If you can't beat them one way, just try another.
Maybe Ms. Jackson should have thought about the ramifications of making a "complaint/statement" before doing so. It looks like she is now regretting her actions due to the overwhelming support the LFO cheerleaders have received. I don't think that this community has any division on this issue.