To comment on a film about a special sort of politics easily seems like taking a stand on and even within that politics. And I can see that in the United States in 1969 people could get nervous, because it's hard to know how people in an audience will take things (when The Godfather came out in 1972 I saw it in a huge urban theatre with a couple of youth gangs getting in and out of their seats and patrolling the aisles). In the case of Ice, the cast is very good, but very few of them are credited (none of the strong and articulate women), and one may suspect they were afraid of a credit (like an actor worried about playing a character who is gay). But as I see it, this movie is not agitprop, though it contains what you could snip out if you want a word to live by. But make sure it's enough.
Instead, the film runs an hypothesis about its very special sort of politics, and shows what you would have to be to do it, if you want a conceptually total revolution. It is fiction about people who think their acts will be the revolution. The cause supported is a fictional uprising in Mexico: the movement has set fire to oil depots in Port Arthur, Texas, not a real event as far as brief research can tell. With African-Americans with a real and militant cause these revolutionaries have only loose contact, with opposition to the war in Vietnam about which Kramer made a movie it has only an AWOL soldier who is of interest because he could furnish "information." The movie is accurately narrated in fragments: when asked what her vision of the future is a character can only say she knows what she is doing right now. Right now is herding apartment dwellers to see an agitprop movie; right now is shooting a gun.
I can see people are put off by the fragmentation. When I saw this movie in a cinematheque there weren't many in the audience to start with and very few at the end. Yet this may be the best story around about theory-driven violent (revolutionary) action, better than movies about the Baader-Meinhof gang or the Brigata Rossa. In 1970 near Washington Square earnest people did kill themselves while making a bomb.