Who are the tyrants that Hidalgo refers to? Why does he use this term?

Spain, the oppressors

Explanation:

Tyranny is oppressive power exerted by government, at the time their government was Spain, that was who had control over them and who they had to pay. There for I believe he is talking about Spain, their oppressors. Hope this helps  

answer: ‘no one should be discriminated against because he or she is not from a minority group’

because—> affirmative action means ‘a policy or program that provides opportunities for traditionally disadvantaged groups to them overcome the effects of discrimination’