applies more to aftermarket used/partworn/remoulded tyres…
The structural integrity must not be compromised. It should be free of large cuts, any bulges or lumps both internally and externally. No plies or cords should be exposed.
Whether or not cracks are the same as “large cuts” is where the debate may arise, you could well argue that the structural integrity is compromised, the semantics then rest on whether they believe they simply sold you a ‘used car’ or a ‘used car’ including it’s part worn tyres (for which they accept they have responsibility)…
The cracking indicates the rubber is perishing, as all tyres do in the long term, so they’re old and more likely to fail in the short run…
dealerships will do the minimum they believe they can get away with in order to be legally compliant i.e. check tread depth…