It's not about deserving to play or not. It's not like the club treated him harshly. It's about basic human feeling, it's ok to feel sad about someone who looks sad, it's called compassion, and that's it.
Watching Krasic taking his medal and knowing he won't play for us, I'm sure many wished that he will stay and become again important player for us. Especially looking at his previous season with us, and some good memories he brought us.
However watching Alex saluting our fans at our stadium for the last time is something totally different and can't be described with words.
If someone feel the same about Elia and Del Piero than that's the different case.