symbiosis is benefitial for both sides.

Bah. There are 3 types of symbiotic relationships: mutualism, commensalism, and parasitism. In mutualism, both organisms benefit; in commensalism, one organism benefits and the other is unaffected; in parasatism, one organism benefits and the other is harmed.

Therefore, even if the Matrix is parasitic, it is still a symbiotic relationship.