You do realize Luther was catholic......right?
Go back and read all of John 6 in context.
At one time he was a Catholic priest, but then he became a heretic and then finally an apostate. At least that is what I think the record clearly shows.
Lets pretend that I am too dumb to read/understand John 6. Because we are pretending this how about we interpret John 6 the way 95% of literate people have for the past 2000 years - i.e. the Real Presence exists.