UL has finished their product incident report, with response:
"The certification documentation associated with the subject product has been reviewed. The product is found to be in compliance with the applicable requirements for the associated certifications." 
I would guess the very old UL 499 (Electric Heating Appliances) fails to call for the power transformer to be an approved component, to any (standard) requiring a protective element such as a thermal cutout or primary fuse, which is required on everything else per UL 1585 or IEC 61558.
It still begs the question of why other Weller models, and other makes of soldering stations incorporate primary-side protection, as further proof of an error made that nobody will admit.
Weller's engineering and corporate PR response is a brown-eyed mullet (if I get Australian slang).
Regulatory approvals are extremely political between the standards body and committee, the component and product manufacturer and certification agency- there's no hope to fix screw ups like this.
