I know this may seemed funny to some people but I do not find this scene in the episode to be funny at all Rainbow Dash is letting Spitfire yelling at Scootaloo like a military recruit but she isn’t she’s just a kid who is disabled because she doesn’t fly like the other pegasus which I find horrible for her and this episode was making Scootaloo in the wrong but it was actually Rainbow Dash because she was such a jerk in that episode and not only that she being a complete jerk in Session 9 because all Rainbow Dash cares was trying to stay being popular and thinking about herself and when Scootaloo found the Washouts she found them really interesting to her because they were seen as misfits and outcasts just like she was even though they were a dangerous stunt performers and Scootaloo could’ve got hurt if she joined them but she doesn’t know that before she joined them at the computation but when she supported them she started to run a fan base for the Washouts and the made Rainbow Dash really jealous and was trying to make her not joining the Washouts and thinks she would take her to Cloudsdale and teach her a lesson and let Spitfire yelling at her but that doesn’t work out with Scootaloo instead just got traumatized and lose her confidence and how does Rainbow Dash thinking that it could change her mind from joining the Washouts she doesn’t care about that because she’s really disabled and knows that she will never be able to fly and I’m sorry but Rainbow Dash was such a hypocrite in that episode and I can’t stand it!
People thought it was funny because it was a reference to something funny. Spitfire wasn’t acting like a DI at all.
tl;dr