I think that the most clean way to go out of this mess for Weller would be to say that there was a mistake in production, that resulted in the fuse to be omitted, and that they're going to receive the faulty models for recall, and just get some people to solder the goddamn fuse directly to to the transformer's post. Of course, after testing to make sure that the fuse will not prematurely blow, as that would be a pain in the ass to replace.
Of course, that would had to be done in the response to Dave, now it's clear that they did that on purpose, for sheer greed. Still, they need to say "sorry, we made a stupid decision" and recall to solder the fuse there.