Have you gone through the eviction process. [?]Like they say where I hail from: "None a 'yer bizness."
That said, a "scientific" analysis of a "representative sample" of the above links indicates that very few (if any) deal make any mention at all of the case to which we are referring: that is, where the tenant has vacated the premises (leaving their belongings on site) after the landlord has reclaimed possession.
To use just one example that does make mention - California - it says:
Any property of the tenant left on the premises will be turned over to the landlord for storage.
That is - the landlord may not, as you suggest, dispose of it as they will. Rather, they need to put it in storage for the tenant to reclaim it a future date.
And in Florida:
If the renter leaves any personal property at the rental unit, the Florida eviction laws mandate you to notify them in writing. In Florida, the law requires that you give the tenant at least 10 days to claim the property. The 10-day period is if the notice was personally delivered to the renter. If mailed, the tenant has 15 days to claim the property. You can charge the tenant for storage of the property. The costs should be reasonable. If the tenant fails to claim the property within that time, you are at liberty to dispose of it whichever way you please.
Again -- the guidelines (that you yourself posted a link to) clearly state that the landlord may not simply dispose of the property as they see fit. Rather, they need to put it (safely) in storage for a certain minimum period as prescribed by law.
That's just checking 2 of the links that you provided - both of which clearly contradict the assertion you made.