As in, there was a legitimate possibility in the 60s or with OWS that the movement would pick up enough momentum to really shake things up, power-structure-wise.
Don't forget that the civil rights movement actually was shaking things up in the 60s. I suspect that influenced political decisions by magnifying perceived threats to the prevailing social order.
What do you mean by "valid" here? Do you mean they are afraid for society, or themselves?