Why is Picard still mourning Data?
Picard still mourning the destruction of Data doesn't really make sense. They were never that close in "TNG." I can see Geordie being like that since they were actual friends. To me it looks like they're trying to force Picard and Data to be in Kirk and Spock-like friendship, but they never were.
Also, he was a machine. It's kind of stupid to feel that way over a machine.