Molly, I don't think anyone of a "certain generation" is moaning. Don't let it worry you, much less do your head in. Don't be upset at people expressing an opinion. They are certainly not having a go at the kids, nor in fact at most of the teachers. The problem is the law since there are various rules and guidelines about the ratio of teachers to kids as you have touched upon. If the teachers can't get in (ie their roads are blocked, or their childcare is up the swannee) the Head has to take a view as to whether he or she can safely open the school. In this "where there is blame there is a claim culture" I really can't blame them.
Nonetheless, you should accept with some joy that times have changed. I am only 20 years older than you, but I can remember my school closing only once (and that was because the snow drifts were so bad the village was completely cut off - it took my dad going into town in his tractor to fetch emergency supplies for the old folk).