Because after that one event in his life that raised his profile to "hero" status, he has not distinguished himself at all in his personal or professional life since.
As a matter of fact, his career in the Senate has been undistinguished and he was a terrible Senator from my home state of Arizona for years when he would side with the democRATS and stab the GOP in the back.
And then when he did get a chance to redeem himself when he got the GOP nomination for president, he was the WORST Republican candidate for president in my lifetime, outside of Bob Dole maybe.
His involvement in the Keating Five scheme showed his true moral compass. He got caught with his hand in the till. Except for his moniker in the media as Maverick, because he went against the GOP so many times, he sided with the democRATS more than not.
I won't belabor the point anymore, even though I could make a long list of undistinguished events in his "career" in politics after carpetbagging his start in politics by abandoning his first wife for some prettier eye-candy, except to say McCain does not deserve any more praise for his time in politics.
He's still hanging on, trying to backstab Trump every chance he gets. Maybe Trump should have taken the high road and mentioned his name, but McCain has never taken the high road in his life.
See my post above at #48.