They no more "killed Picard off and made him an android" than they did "kill Spock off and make him a clone." It's the same Spock in a new body at the end of TSFS; it's the same Picard in a new body at the end of PIC S1.
This right here. How many times has something similar happened in Trek?
Spock died, and was replaced by Genesis Clone Spock.
Harry Kim died, and was replaced by Slightly-Alternate-Universe Harry Kim.
Jadzia Dax died, and then became Ezri Dax.
Picard died once before, but then Q pulled some shenanigan's to make him not die.
Neelix died, and then Borg nanoprobes brought him back to life.
Culber died, and then... whatever the hell happened to Culber happened and we have like, Mushroom Culber?
Shax died, and then he just like, left the afterlife and came back.
Data died. And then he didn't. And then he did. And then he didn't again.
It's really nothing new.