These big mining pools are the only ones that becomes centralized they have 47% of the total hash rate meaning it's still not centralized there are 53% of the total hashrate is still on decentralized pools and other miners can still mine on other pools if they don't want to mine on a centralized mining pool.
These pools are not centralized because they store their block rewards in a custodial service, i know it sounds 'weird' that all 9 of them chose the same custodial service, Cobo, but it is not for this reason that they can be called centralized. If a pool starts 'taking orders' from the government on addresses and utxo's that should be blacklisted, i believe that is when you can call that pool centralized.