Hmm...would he be wrong? We are pretty horrible.
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Of the Mane Six:
I agree with Scootaloo Is Best Filly--I think Twilight Sparkle would be compassionate towards, and excited to help, humans. She would eventually be forced to give up, of course...humanity is unwilling to be helped.
I think Applejack would likely have the lowest opinion of us; we're lazy and often take the easy way out. Also, many of us (at least in much of the modern, westernized world) are disloyal and cruel to our kin. AJ has firm opinions on what is right and what is wrong--I think she would take a while to see the good in mankind.