Since Jesus is the fundamental standard (ie. an absolute) then Jesus was a fundamentalist. What the Pope is ultimately saying is that Jesus is not a Christian as the Pope understands Christianity and moreover that Jesus was “doing evil.” Jesus believed in absolute truth and in the High Holy Prayer he defined it as God’s word. “Your word is truth”
Was the Pope sitting next to Obama during the “Reverend” Wright years? WTF, over?
The term "Fundamentalist" in the United States derives, historically, from that.
So, there's a definition problem here. POpe Francis isn't using (whatever-word-in-Italian) "fundamentalist" to mean, in the American Protestant sense, somebody to believes in the doctrinal positions explained and defended in "The Fundamentals."
I don't think that outside of the USA,the use of the word "fundamentalist" is even known in this sense. In the rest of the world, it just means the equivalent of fanatic/zealot/extremist/nut.
The word in that sense is applied not just to Protestants, but to Catholics and Orthodox (who might have different, contrasting doctrinal points) and also Jews, Muslims, Hindus, Marxists, Vegetarians, -- it means a person who has a kind of monomaniaal attachment to some ideology.
So although Pope Francis certainly does say very dubious things from time to time, IN THIS CASE he is not insulting Protestantism or Evangelicalism per se.