The stupidest part is (obviously with hindsight, but still) he could've so easily handled it like this:
Do nothing initially, I guess maybe glare at Chris if you wanted...
Then when you go up to accept Best Actor you can say your piece:
"I thought they usually get a comedian to host these things...
naah but really I'm so glad the awards are so much more inclusive now;
they'll let you be the host even if you can't come up with good jokes..."
Stick in an extra line about how he still thinks she's beautiful no matter what etc. jobs a goodun' he comes out not looking like a **** and hopefully salvages things