I completly agree, blocking client downloads is a bad idea.

As I told on Bearshare.net this download blocking idea isn't good at all. Stoping a bad client (with wild broadcasts) from connecting to the Gnutella network would make more sense and should be discussed together with all other developers (e.g GDF) first. Bearshare is not the only client. But I doubt Xolox is bad (hope we can discuss this tonight on IRC), Vinnie didn't give any facts or statistics, I doubt he has a brief understanding or analysis of what Xolox does.
So I personally think Vinnie's new idea is just about marketing. Vinnie was not able to implement a fast multisegmented download or partial upload the last 4 months (some of Xolox new features and benefits), also no superpeer concept in Bearshare, Vinnie's "Defender" is dead. Xolox is still one of the best clients, more clients come with fast downloads & a good resume, Limwire will come with a FastTrack-like superpeer concept.... and Vinnie only badmouth some competitors to make Bearshare look better. Poor marketing. The old story again, this is anoying. *sigh*