If they do not do anything nor think about their doing or not doing anything about ever again, then I wouldn’t call it passive-aggressive. But, if they do not do anything but wonder if they should have or have it all fester inside them and then explode on the person re: a different matter but it’s really about the milk, then yea, that’s pretty passive-aggressive. If it is something that bothers a person but they pretend it doesn’t, that’s kind of how I draw the line.