Thanks for all your feedback, though I have to say that I have calmed down and found my way back to some old familiar pathways in Ancestry, many of them as absorbing as ever. I did resign from my full membership, however, once I realised that Fold3 and newspapers.com were of no use to me.
I have learned to take the public family trees with a grain of salt because many of them simply mimic vaguely inaccurate information picked up from other people. The most worrying example was a verified ancestor of my husband's married off to someone in Orlando, Florida which he, most decidedly, was not.
Should I just ignore it, or make an effort to set the record straight?