Hi Gene,
I made the same mistake early on of sending my entire GEDCOM to other people and, like you, later found my immediate family posted on WCP by one or two of those people. Fortunately, they were responsive to my request to remove data on younger generations. If you haven't tried contacting the offending person in your case, it may be worth it to do so. Also like you, I now only send reports on portions of direct lines to people with common ancestors, and do not permit downloads at all from my GEDCOM.
My opinion doesn't seem to count for much at RootsWeb, but I'll still throw in my two pennies worth: I oppose an option allowing others to download entire GEDCOMs. Even if the contributor of the GEDCOM has the ability to not permit the option, once there who knows what could happen. I'd feel better if the option was not available at all.
Thera