Of course we can't blame Sesame Workshop for the ad. But keep in mind that PBS has been a thinly disguised propaganda arm of the Democrat Party for a long time.
And, I'm betting they are "doing the right thing" because it is politically expedient and want to avoid a PR disaster. I wouldn't give them too many kudos for be morally upright.
It’s hard to prove that one way or the other, but I will say they certainly responded to the production of this ad very quickly.