Your whole argument is based on unperishable food being spiritual based only on personal understanding. Your basing your argument on a sola scriptora basis but you are going beyond what is said. Your even speculaing on what the crown was thinking and not what they said. Yes I agree that the jews around him were confused and most likely were confused when they departed but they were confused for different reasons.

Verse 34 the jews say give us this bread. At this point I think we agree to some point that they were looking for a phsical bread to eat just to fill their stomachs.

Verse 41 They questioned him about Jesus saying he was the living bread. I think even at this point we can agree on the principal that Jesus in some way is the living bread. And I think we also agree that they questioned him about How can he come down from heaven.

Up to verse 50 I see no reason besides speculation to why the bread that he was about to give was only spiritual in nature. If you read john 6 with the idea he was talking about the eucharist it does make sense.