Actually if you estimate the time required it's plausible that player feeding comes out on top, especially if setting up automation is not that obvious. But human player would never play that way, they would get bored from the repetitiveness, and the micro scheduling would be a headache. So the game designers never really have to close that gameplay loophole (or closing it would make human experience worse).
I have a similar problem on my GK2 vibegamed playthrough (see https://news.ycombinator.com/item?id=50302771), if I want computer to play similar to how a human would, I need to artificially close that loophole (for example, AI prefers to gather/eat low-tier food to cooking better).
Anyone making this claim just hasn't played a lot of factorio, because this just isn't true. Player feeding is fast in the early game, but it just doesn't scale. There's too many buildings to feed and it takes too long to walk between them. People have already made tool assisted speedruns, and as expected it involves building a huge automated factory as quickly as possible.