You can read Peter Gelderloos' "How non violence protects the state", where he returns to another history of the Black Panthers. Especially arguing (without denying the BPP's sexism) that they were not much sexist than most of organisations of the Left and militants groups at this period of history (and maybe not very much more than many of today). Whether they had been violent (as the weather underground and the violent sexism between its members, or the italian red brigades who took a clear antifeminist stance, for example), or even non-violent figures as Gandhi or Luther King's SCLC and his misogyny and homophobia, etc, etc.
At least as the panthers were black and assumed the need of revolutionnary violence, their sexism was emphasized as an argument to discredit them. But the reality is a little bit more complicated. You can read more here (and in the rest of the book) : http://theanarchistlibrary.org/library/peter-gelderloos-how-nonviolence-protects-the-state#toc5
Otherwise, there is a good text criticizing the black panther party on an anarchist perspective, but still anecdotally. It's "How I became an anarchist ?" (http://theanarchistlibrary.org/library/ken-knabb-confessions-of-a-mild-mannered-enemy-of-the-state#toc8
), written by an oakland anarchist which is none other than Ken Knabb, who lived there at the time and where the BPP was founded. It points some criticism against the black panther party on its very caricatural orthodox marxist organisation and some other pretence. Still incomplete as it don't point at all the positive radical aspects, but interesting.
Much complete on a theorical point of view, is Murray Bookchin's "Anarchy and organization : a letter to the Left", which is a short text written in response to Huey Newton (founding member of the Black Panthers) attack against anarchist forms of organization. You can read it here : http://dwardmac.pitzer.edu/Anarchist_Archives/bookchin/leftletterprint.html
And last but not least, this text of Bookchin is on the "suggested readings" of Ashanti Alston's "anarchist panther zine" website. This guy is a ancient black panther, ancient member of the black liberation army who get jailed for years and became an anarchist in prison. Even he have a very special interpretation of anarchism (as a mix of some psychological critical thinking, maoist and "revolutionnary left nationalist" influences) he developped a very intersting criticism of his own experience and of the Left on an anarchist perpsective with an insider experience of the movement and of course as a black man. You can read it here : http://www.anarchistpanther.net/index.html
I suggest you to begin with the text called "One journey into and out of the anarchist... BLACK !", which is a good introduction to his words and particular writing style.