In my experience, first-party JavaScript is more likely to be updated so rarely that bugs and exploits are more likely than supply chain attacks. If I heard about NPM getting attacked as often as I hear about CDNs getting attacked, I’d be more concerned.
Just went ahead and Googled it and I can find no credible source that he actually said these words at any time. So, if you’d like to bandy out that source, I think we’d all appreciate it.