I question ProtoAvatar's assumption that a thalaron weapon would even work on the Borg.
It's not my assumption. It's 7 of 9's - who knows more about the borg than me, you or any other real person can ever hope to find out.
Um, actually, she only knows what the authors decide she knows, and the true nature of the Borg is whatever the authors decide it is.
And since Christopher
is one of those authors....