After i can now add the metamask address where my Ledger Ethereum adress is presents (because i just imported it)
Just to make sure, are you connecting your Ledger With Metamask or are you importing the Ledger's seed phrase to MetaMask?
1. How Metamask can send token to a ledger address that normally is not supported by Ledger ?
If you use/connect MetaMask with Ledger, MetaMask is just the one who manages the interaction between web3 services/platforms with your account/address. So Ledger or any hardware wallet just functioned as an approver who processes the interaction with the address private keys, things like signing messages, sending funds, and interacting with smart contracts.
Since Ledger Live does not as flexible as MetaMask, some functionality is not available.
2. How Ledger can receive theses tokens if it's supposed to not support this blockchain ?
Ledger Live won't show it, but the hardware wallet itself received the tokens.