Did Sam kinda forget

I don't understand Sam's critique of Daenerys that she didn't spare life of Randall and Dickon and executed them.

Yet, when Jon sentenced Janos, he begged for mercy and said that he's sorry. Sam was there and Jon didn't spare Janos life.

Some do execute their prisoners and some don't, it's not big of a deal, it's really up to a leader. When Robb didn't want to execute Lannisters prisoners he wasn't praised for that and mostly hated. Sam's critique of Daenerys that she is somehow not a good Queen based on fair execution of 2 men that align with rules of war is quite weak for me.