I concur -- let it go.After all what are they taking from you?
When I first started, I was cutting and pasting like crazy, but as I moved from 'collector' to researcher I've stopped doing that.I stopped not because it was wrong, but because it wasn't really getting me anywhere.
My own primary source research or work that was done by a professional for my family is all posted on the web.I'm happy for anyone to take it as they like, after all that stuff all came from public records.
Unless you're adding specific commentary -- i.e. creating a new, original work, what are they taking from you?a list of dead people and copies of public records?There's really no such thing as theft of data which is ALREADY IN THE PUBLIC DOMAIN.
Are they taking your credit?The people you're doing this for (presumably yourself and your more immediate family members) know what you're doing and if they don't appreciate it now, they will someday.And other researchers definitely can tell when someone is the real McCoy.
Are they taking your opportunity for financial gain?You've already forfitted that chance by posting it on the web.One researcher I know posted cemetery information he had hand transcribed from tombstones on the web free to all and he knew people would be copying it.He did ask that people not sell it and to try not to provide it to a commercial data distributor.This seems to me, honorable and reasonable.