You mean the lying NYT reporter playing fake baby.
In my opinion, Trump was obviously mocking the reporter. At the same time, in my opinion, the reporter obviously deserves to be mocked. Regardless of what he did or did not report in 2001 (that's a bit hazy, since his initial article didn't technically report that there were celebrations, only that there were "allegedly" celebrations - like a good MSM soldier forced to report on a story that goes against the left's narrative, he wrote it in a deliberately vague and deniable manner), the guy's little trip up to Wasilla to dig up dirt on Palin shows exactly what kind of scumbag he is.
So, in short - yeah, Trump was probably mocking him, but screw him anyway.