Recent judgements against anti-abortion sites have established that what you say on the web is indeed actionable, even when no falsehood is involved. It is unquestionable that your reputation has been damaged by the Wiesenthal Center. These lists are truly outrageous. I would include all innocuous groups listed on the various Wiesenthal Center hate pages - there are several. The Wiesenthal center has assets and is definitely collectable.
Lawyers profit inordinately from class actions.
By notifying the other innocuous sites, you will be extending the number of angry damaged parties seeking a means of legal remedy. Eventually, someone will find the right legal firm. Even if you don't have the energy to undertake this yourself, some webmaster you contact will have the steam to chase this down, or enough will work in concert to get the job done. Don't include the genuinely offensive sites. Don't waste energy and compromise your case by public discussion with yahoos.