I think he's pointing out that mining pool operators create the block templates and block templates specify which transactions get into blocks and which don't. So even if mining were perfectly decentralized, pools, which are necessarily centralized to smooth out mining rewards, pose a centralization/censorship risk.

Stratum V2 fixes this by letting miners select block templates themselves. But it's not being deployed let alone tested by miners yet. @bluematt shamed them on TFTC recently. They discuss the discovery that >51% of hashrate already belongs to one "pool of pools".

Of course, there's also manufacturing/supply chain centralization to worry about, and the super cluster of miners currently in Texas.