‘If you can’t cope with the ants, don’t mess with the anthill.” So goes a slogan chanted by the activists occupying land belonging to a sugarcane processing plant in the north-eastern Brazilian town of Santa Helena – one branch of the Landless Workers Movement (MST) that has been battling for land access for smallholder farmers in the country since 1984. The cause is unimpeachable, and even more pressing with Jair Bolsonaro’s current backing for ruthless agribusiness whose giant footprint excludes almost everyone else.

So it’s surprising that the effect of this advocatory and visually sharp documentary – director Camila Freitas’s feature-length debut – is somewhat deadening. Filmed over four years, it forgoes commentary, simply accompanying the peasant-activists as they daydream about how to allocate the terrain, debate their principles, and try to win hearts and minds in town. Structured around long dialogue scenes shot through with testimony of injustice and struggle, it finally exudes a strange passivity despite all the idealism being traded. No charismatic individual strong enough to carry the film emerges; the rounds of protest against the status quo, away from the fields, seem Sisyphean.

Perhaps the conservative forces ranged against them are too great to expect such a breakthrough. But Freitas’s instinct is essentially passive, too, refusing to dramatise undercurrents and factions in the movement that might benefit from more historical explanation.

Even the film’s visual power feeds this feeling of futility. The ravishing shots that punctuate the conversations emphasise the unyielding system, as with one of listless judges staring into space in the courtroom. But otherwise they return to the landscape, the eternal need to till and tend, and the serene indifference of nature. Reflection, not revolution, seems the only viable option.

• Landless is available on Mubi from 21 July.