Did you see the elaborate video for Freddy Mercury’s birthday? They have fancy doodles for the most trivial things, but for 9/11 they add a black ribbon and three words. That must have taken all of .5 second to do. Pathetic, but frankly, I’m surprised they remembered at all.
Google’s “Doodles” are typically irreverant/silly/etc. They simply don’t do “doodles” for somber/serious events. I have no problem with their understated approach - I agree with the Freeper above who described it as somber and appropriate.