They probably meant from a developer perspective. It's the only browser that's missing a lot of CSS/JS features and needs weird workarounds for the simplest things.
Apple has been suspected to intentionally slow down safari development in some key areas so it won't cannibalize the AppStore. Frustrated web devs, unable to get their web apps to work correctly on safari mobile, would publish their apps in the AppStore instead of using PWA.
That has been mostly solved by Apple in the most Apple way possible. They just forbade PWA on iOS. Period. Like, they still load on Safari, but you can't pin it as a pwa to your app drawer anymore.