On how "authentic" your voice must be:

Many of you may have seen this: http://nativeappropriations.blogspot.co.uk/2012/07/real-indians-dont-care-about-tonto.html (I recommend reading all her blog, it's awesome).

It's about the efforts of a small group of people to shut down the voice and blog of a blogger by questioning her qualifications for discussing stereotypes and accusing her of disrespect amongst other things because she spoke up about hurtful stereotypes and how harmful a role Tonto is, with or without the dead bird.

If you are a blogger or a equal rights activist, you will face this sooner or later, I have. When I speak up asking people not to say hurtful things about the disabled, people question my "right", they question my disability, not because there is any question of it but because rather than address if what they said is truly hurtful, they instead choose to attack me and my validity, this says louder than words that what they said was indeed hurtful and wrong.

When people question your validity it is because they cannot argue with your point. When they say you are not disabled, female, trans, non-hetero, non-white, poor, or indeed enough of any minority enough to speak up, what they really mean is "you said something I cannot construct an argument against so I will question your right to question in the first place".

They will say that you are inappropriate, they will say you are rude, they will say you are disrespectful, they will say you are a fake, they will question your credibility because if you are authentic then they have to face that they said or did something inappropriate, and I find that a lot of bigots are unwilling to admit the chance that they could ever be inappropriate ever much less confess to the reality that they are.

They will declare you to not be a feminist, to not be for equality, to not be part of the group you are a part of, they will demand that you prove your membership as if they have a right to do so. They do not have this right.

They don't believe or care about what they question, they only care about shutting you down and out. It is your voice they want silenced, and their method to do it is to attack how "authentic" you are.

Remember this when you speak up and do not let their attacks cause you to doubt your own voice, because anyone who only can "refute" you by questioning your right to speak has no better argument against what you say and is in an agony of outrage that they might have to admit that they were wrong.