What I posted is exit poll data from election night. What you're linking to are "political leanings" from 9 months before the election.
Had these "political leanings" held true, Trump would not be the president. People either switched to Trump, or many "mainline" Protestants did not vote. Probably a combination of the above.
But either way, it does not change the fact that *Christians* were the force that elected Donald Trump. The aggregate category "Protestant/Other Christian" reported voted Trump over Clinton 58:39. How many Mormons would it take to overturn the "mainline Protestant" vote like that? "Protestant/Other Christian" was 52% of the electorate. How much of that 52% would you count as "mainline"? 80%? Let's do some approximations.
A couple of other things I note...
1) Jon claimed that, "The only group Trump did really well with were the fundys." There's no line exclusively for fundamentalists on the data you provided.
2) Pew erred by lumping together Protestants, Mormons and other Christians together to form the group "Protestant/other Christian," since Mormons are not Christians.