Never owned a Tesla, but the amount of horror stories involved with Tesla, its often a hard battle to get warranty, especially around the battery when it involves a second hand vehicle. Even first owner vehicles are often a mixed experience.
I assumed you never opened the link you point to, as its literally in the first line very clearly "Your new Tesla" (as in, not a second hand vehicle). Ooooo, fun, look a bit lower in the actual model info. Your vehicle need to return to the first registered area to gain warranty for a resell. Here in Europe we see often cars being sold that come from Spain or other area's, in Germany. By that contract condition, it need to go back to Spain for a battery fix. lol
Tesla Vehicle warranty is at discretion of Tesla bla bla ... Battery max 8 years, or 240.000km, ... Lots of other exceptions to that warranty.
And if you can apply the warranty, your also not getting a new battery, but a refurb based upon the whole description.
Fyi: Lithium batteries drop in capacity faster and faster when they go past the 80% mark. But legally, Tesla can shove anything in there. A 100% battery, a 80% battery, ... you get the point.
With a ICE engine, even on rental cars, you tend to get the same millage out of them, as a new one. Most issues are often more on the clutch or turbo, both relative cheap repairs compared to a battery pack.
People have been warned years ago, that second hand market for EV cars is going to be a issue because of the battery. Now we are seeing the effect on the pricing.
A lot of these used to be leased cars. Why would those batteries be dead?
And if they are under the 70% mark then Tesla warranty should cover that. See https://www.tesla.com/support/vehicle-warranty