The phrase "are often manipulated" is correct and usable in written English.
It can be used to describe situations where something is frequently controlled or influenced in a deceptive or unfair manner.
Example: "In the world of advertising, consumer perceptions are often manipulated to create a false sense of need."
Alternatives: "are frequently influenced" or "are commonly controlled".
They wield their power so deftly that other characters are often manipulated without their knowledge, but we, the audience, know.
But they say that squatters are often manipulated by developers, or even by corrupt local officials of the institute.
Victims of sexual slavery are often manipulated into believing that they are being relocated to work in legitimate forms of employment.
Given that fire regimes are often manipulated to maintain plant diversity at the landscape scale, detecting and disentangling fire from environmental effects at this scale is important.
In a country where courts are often manipulated by the authorities for personal and political gain, few, particularly Mr. Orlov, thought he stood much chance of beating the charges.
Things here are often manipulated for politics.
Reflecting the lax standards in national politics, the state was often manipulated by corrupt politicians.
We've lost the memory skills that oral storytelling cultivates, and we're often manipulated and distracted by seductive writing.
Surface tension of fluids is an important factor controlling multiphase systems and is often manipulated by surfactants during industrial processes.
Political mechanisms: The authors argue that more social science research is needed in order to reveal and better understand how the political process is often manipulated.
When legal proceedings were possible, they were often manipulated or frustrated by the crown's "overmighty subjects," who intimidated and corrupted justices, sheriffs, juries, and witnesses.
