I do not agree.  Do you believe that God would care who partook of the Eucharist - Jesus shared Himself for all mankind.  It would be meaningless as a spiritual source for someone who does not believe that Jesus told us to "do this in memory of me."  For the unbeliever, it is a piece of bread.  But for someone who does believe, it is a sacred act and Jesus presence is realized by believers in the communal sharing of bread in His memory.

Christ is present in spirit because of the faith of the believer.