It’s the way things work with online commerce. Sellers assume risks with product damage until delivery (no matter the reason). I’m not saying it’s always fair but it’s the best option.
With that said (and agreed!) on, I know some retailers or at least web stores are adding in language to cover themselves. I think we have seen that on those $1 route protection charges, so that may be shifting a bit. However, given Amazon's super hassle free return policy (you don't even need to pack the item back up anymore, just bring it to a UPS store) and Paypal's very buyer friendly default position, this is probably how most retailers are forced to be.
It'll be interesting to see if and how that shifts over time. I know other collectable companies are much less amenable on this front, so this could shift I guess.
I never had an issue with Bull Moose but I rarely have their stuff shipped since I have a store 20 miles down the road I visit twice a month anyway, so I usually just pickup. The mailers seemed pretty sturdy though so definitely an unfortunate series of events there.