Perhaps look at it another way - assigning a Nobel peace prize is a way of putting wider attention onto someone, and maybe works as a soft pressure to keep them behaving a little? For half a year or so after you get awarded a peace prize, your profile in the world is a lot higher than normal, perhaps giving you a bit more of a nudge in the right direction.

Also, Aung San Suu Kyi won her Nobel Peace Prize in 1991, 26 years ago. How old is that? Well, that was the year that the world-wide-web was born. Kurt Cobain was still alive. George Bush was in office and was just 'George Bush', not 'George Bush Sr' (and the first Bush war against Iraq started in January). The Soviet Union still existed, dissolved only in December of that year. Street Fighter II hit the arcades. The Rodney King beating sparked the LA riots. The war that gave us the term 'ethnic cleansing' started that year in Yugoslavia. Apartheid was still going on in South Africa, with a couple of years left to go. Linus Torvalds announces Linux on comp.os.minix.

Calling the Nobel Peace Prize bullshit because a recipient behaves differently-to-expected a generation later is itself bullshit.