sending "junk mail" and demanding customers "return it" is technically illegal (or at least it used to be)
So what you are saying is:
If you claim a package gets lost and you want a replacement sent, if you wind up getting both packages you are perfectly happy to just say tough luck all mine screw everybody & don't bother trying to get it back bitches, I don't care if you lost money, I don't care if you are out the product twice because the carrier refused the insurance claim since they actually eventually delivered it. All mine that, honesty thing that's only for others.
And no you are actually wrong.
You are trying to use old rules that you couldn't send someone something completely unsolicited and demand payment for it, to justify dishonest theft.
You directly solicited the shipment of the original item, you directly demanded a shipment of a second item based on not having received the first one.
Very different scenarios. I guess honesty wasn't your thing.
If you filed a statement saying you didn't get a package and demanding a refund or replacement, that you get.
The seller has every right to require you to return the first one if they so wish if you get both.
But of course you wouldn't be interested in actually being honest would you?
That's pretty much the EXACT reason you have to wait before sending a replacement until all the trace work is done and the package is declared lost by the carrier and you are able to file a claim.
Because, well people like you...
A decent person would actually contact the seller, offer to ship it back perfectly unopened, or pay them for it if they wanted it.
But like I've pointed out above, buyers seem to be happy to be dishonest all they want.
Oh and how we've dealt with folks like you....
File a police report for fraud and theft if local, send it to an aggressive collection agency if distant.
Most eventually understand they aren't getting to keep stuff for free that they didn't pay for.