Who has an interest in perceiving this opposition as a structural weakness rather than as a nuanced application? The presumption of market integrity is not logically opposed to negative fraud tactics; the issue rather lies in the asymmetry of incentives and the consequences.
If this presumption were systematically weakened, the cost for complainants would increase, as evidenced by the difficulty for a pension fund to prove its individual dependence if an issuer spreads false negative information for a low-price share buyback.
The Nash equilibrium would be disrupted, prompting malicious actors to abandon market confidence.
This poses a generalized defection risk of trust in market prices.