I agree with what everyone here has stated - Deep Purple, Yes, and in my opinion, the Moody Blues, all should be in there. Several bands who Purple influenced are already in, which just defies any logic at all.
I like rock, the harder the better generally. But over time, my view towards the Hall of Shame has lessened just 1/10 of an ounce. Why? Because "Rock and Roll" has been around longer than I have been alive (I am 48). Rock and Roll itself has evolved through many decades, and spawned so many offshoots of Rock and Roll, it is almost crazy to keep track of them all. So to truly be the Rock and Roll Hall of Fame, they should span many genres of Rock and Roll other than what is popular to anyone today. To take Purple into account - who were their influences? Purple influenced countless bands, those who made it and those who did not, and those who played "pure hard rock" and those who did not. So to say Purple deserve it on any basis of influence, you'd have to give a nod to those who influenced them too. And yeah, some of those bands are already in the Hall of Shame, thankfully.
Hey, if it was up to me, Rap and Disco would not be in the Hall of Shame. It would only be "true rock and roll". I think the reasoning behind why bands are allowed to be in the Hall is sound, but the approach for qualifications "they" use reminds me of what Jesus in the Bible stated - "Father forgive them, for they know not what they do".