Well, Starscream is kind shit compared to other transformers. He rarely won a battle with his skills, but normally backstabbing the opponent, and also have the Villain's Curse of shitty aim and thinking that he is the best guy around. Easy win for Rainbow Dash.
Not to mention the fact that this particular pony (Rainbow Dash) is actually, kinda powerful. Super speed, increased strength, control over the weather...blah. If it was any other transformer she'd be fucked.
in my opinion Starscream should've won cause you know Giant Robot vs Little Horse i mean come on no contest giant robot and yes I'm an anti-brony but even if wasn't I'd still think the same. But again this is my personal opinion
Also, GiantvsSmall Horse doesn't help. That's called judging something before you actually see it in action. That sort of thinking is why a lot of fighters lose against snot nosed kids. Need I remind you Spiderman VS a Champion Wrestler in the first Spiderman Movie? Small kid against huge macho guy. Who won? The skinny kid.
This match was indeed fair, none of the death battles are won by fan base, if that was the case then Kratos and Zelda would have won...but no. Also if would not make since becuse there is no generation 1 rainbow dash, what they did was they took Hasbro closet comi.tetion Starscream the Original and the Original Rainbow dash(since there wasn't a rainbow dash in season 1) and had them fight....this will be my most fav fight out of them all.