I mean... when you confess about KILLING 50+ more/less innocent (though backwards) people... you'd think there'd be some more emotions...
gotta stop ya right there.
He's a Jedi (or at least has been trained as such, up to this point).
"there is no emotion, there is peace."
He is trained to NOT show or act on emotion (though the massacre was indeed emotionally motivated!)
He's in a transitional phase during that scene. He has caved to the temptation of the dark side, and committed
emotionally motivated violence (though arguably justifiable, or at least understandable; those people slaughtered his family... most people would want revenge... but he happened to be force-sensitive AND Jedi Trained, so he had the means to do so). He's not "evil" yet... but he's opened the door, stepped through, had a look around, and stayed a while. But then he felt bad (really bad!) about it... though he's still conflicted, because he doesn't feel TOTALLY bad about it. He's like "i feel terrible... mostly... but i also kinda feel they deserved it... but i think this means i've failed as a Jedi!" (although technically, it could be argued that he never officially ascended from Padawan to Jedi status, and the massacre was a large part of the reason why... which was motivated by fear and anger, which are things all Jedi are supposed to overcome)
Idk, i think it makes more sense if you've seen the OT first (because then you'd already know...
More
he eventually redeems himself at the end of ROTJ, in his final moments... and all because Luke is such a BAMF.
)