Sam vs Milk

Went and saw "Milk" the other night. I thought it was a really good movie but I have a quibble...Sean Penn's portrayal of Harvey Milk. For the most part, I thought it was great but there were moments in the film when I swear Penn was channeling the character he played in "I am Sam". On the one hand we have a gay activist and on the other, a retarded man fighting for custody of his child. You couldn't ask for more different characters but still, during some of the early parts of the film, Sam and Harvey merged into one.