It addresses the comment that essentially boiled down to "why would they want this, letter bombs almost never happen", and I simply have shown other reasons for why they might want it. I wasn't addressing the article, I was addressing a specific comment.

>Do you really think people who are going to beat USPS workers are going to post about it online [...]

Yes, it does happen. People publicly post on twitter about their plans to vandalize property and such, so I don't see this scenario out of reach at all.

>[...] and that the USPS would be better equipped than agencies whose sole purpose is to deal with these kind of things?

No, but USPS would be able to use this as a clue of something brewing and make the relevant agencies aware, all while dealing with ad-hoc mitigations (e.g., if the threat seems credible on the surface, prepare tentative re-routing plans for their drivers to avoid that area, in case the agencies confirm that the threat is credible; if the agencies confirm that the threat isn't credible, everything proceeds as usual).