The phrase "activists maintain that" is correct and usable in written English.
It can be used when presenting the beliefs or assertions of activists regarding a particular issue or topic.
Example: "Activists maintain that climate change is the most pressing issue of our time and requires immediate action."
Alternatives: "activists assert that" or "activists claim that".
But human rights activists maintain that Rwanda too often suppresses political opposition and free speech.
Some scholars and activists maintain that what's missing are in-depth statistics regarding women and girls victimized by police.
Activists maintain that the demands of the 2011 uprising, such as an end to police brutality, are a long way away from being achieved.
Activists maintain that the government strikes are responses to insurgent gains in a campaign designed to blunt the air power that has helped give President Bashar al-Assad an edge in countering the insurgency.
Many others, though, including Senator John Kerry, some other members of Congress from both parties and a variety of serious-minded activists, maintain that the standard has already been met.
Activists maintain that the public never heard from the rural diner types, because those workers — the ones most in need of a higher minimum wage — are generally not in a position to complain about their earnings or to take time off work.
The activists maintained that the Treasury should have taken measures to ensure that public money was spent in ways that did not undermine human rights or contribute to climate change when bailing out the bank in Scotland in the aftermath of the subprime lending crisis.
Will they maintain that pace?
Consequently, scientists defending animal experiments insist they are essential for safe clinical trials, whereas animal-rights activists vehemently maintain that they are useless [ 162].
Training helps activists maintain discipline.
The parents poised to boycott, led by Skid Row community activist Alice Callaghan, maintain that their repeated requests for English-only classes at Ninth Street School have been ignored, despite district guidelines that allow parents to choose the language of instruction.
