Right. Han shot Greedo because Greedo was pointing a weapon at him and had threatened to kill him. The killing was justified.
But the Mandolorian shot Jawas who were
not threatening him, and who (as far as we know) had never threatened to kill him. That's a new precedent in the SW universe.
One of the unwritten codes in the SW universe -- and really it's one of the unwritten rules of modern fiction -- is that you can't glorify murder or else you're gonna lose the audience.
In fact, the old
Hays Code specifically addressed this (
"If someone performed an immoral act, they had to be punished on screen").
Obviously, no one is expected to follow that code today. But the principles of the code have a basis in reality: audiences don't like it when perceived good guys do bad things. It's a turnoff.
And George Lucas inherently understood this, which is why he never had any of this good guys commit acts of evil. They only killed killers (or people who actively supported killers). That's why he changed "Han shoots first" -- because he was disturbed by the idea of one of the heroes of his story committing murder.
To me, it's a little sad to see Star Wars lowering the bar and delving into a territory that it had strived to avoid for the past 42 years.