Zeropaid has it too:

BearShare Blocks other Gnutella Clients
After months of badmouthing and disadvantaging other clients here is it finally. From Bearshare.Net: "You can choose to receive all query replies, downloads and uploads only from other BearShare clients". In clear works again: Bearshare is splitting the network! Remember the words from hackmaster Dr. Damn: Be nice and play fair. Uninstall BearShare.

http://www.zeropaid.com/news/article.../06272002g.php