Yes, the human brain is not a computer, the two are just not comparable. That said, given Star Trek's fantastical science and technology of the late 24th & early 25th century, "copying the consciousness" has been a thing, so I can handwave that. In the case of human and synth Picard... even if you "move" his consciousness from his human brain to his synth brain by "cut and paste," the original is still being deleted, which is still the death of the original Picard. Whether brain function is lost via cut-and-paste or via brain anomaly, it's still the death of the original Picard. Synth Picard is a copy, granted a "perfect" copy as far as anyone knows.