Who says there has to be only one voice? "We" don't have to do any lumping. People who have similar interests form their own coalitions - just like in any political lobbying. I've never claimed that these groups are homogenous or that they should be, although there are knowable sociological elements that different demographics experience in general - and we can speak to those trends.
Each group can put forth advocacy for what they see as important and then we can engage in discussion about how to address their needs - some of which may be competing. No-one is shutting down discussion (unless the things that you are saying are offensive and out of touch with reality). The alternative that you seem to be suggesting is that people who are hurting should all sit down and shut up and just hope and pray that through the grace of who knows that their needs will somehow be addressed.
And who says that advocates have to be perfect? Dr. King certainly wasn't. I have absolutely no issues with calling out individuals or groups who are themselves perpetrating harm or acting out of integrity, but scoffing at the idea that people shouldn't band together with others who have similar intererests and issues to advocate for themselves is absurd. As I've already pointed out several times, white men do this all the time. We think of it as mainstream society.
And I didn't say minority group - I said marginalized group, e.g., groups and communities that experience discrimination and exclusion (social, political and economic) because of unequal power relationships across economic, political, social and cultural dimensions. All sorts of people might come under that umbrella, and they all have every right to advocate for their interests and needs.
I'm sorry, but you haven't made any case for yourself at all. You've done nothing but throw out red herrings about it being an imperfect process. Well, of course it is. Noone has said differently. You dismissing deeply impactful and systemic harm that many people who aren't penguins have to face as "arbitrarily decided facets of identity" is mindbogglingly callous. And since I don't experience you as a bad penguin, I'm going to chalk it up to the cluelessness that comes from being near the top of the dominance hierarchy.
