I think there is some positive effect potential for Apple to let this slide. The broader this network is, the more adoption it receives. P2P as a super-structure has always been a bigger than vendor problem; adoption by any means is likely an allowable tradeoff, especially since Apple doesn't have to do the work here.
Eventually they will capitalize more on the mesh density, rather than crushing the adoption now.
Except that custom tags like these do not require an Apple device in order to use them, so the size of the network is not increased. They only increase the load on the network. FindMy is not a P2P/mesh network; all these tags do is broadcast keys which are picked up by iDevices, which then upload those reports to Apple.
Two master secrets are randomly generated when pairing the AirTag for the first time, which are then saved to the iCloud keychain. Those secrets are then used to generate a new keypair every 15 minutes (at most), and the public key is broadcasted by the tag. Not only does Apple not know what the master secrets are in the first place (because they're stored in the keychain), but that's also an insane number of keys to compare against, with no real possibility to precompute them. And that's a big win in terms of privacy.
Eventually they will capitalize more on the mesh density, rather than crushing the adoption now.