There should be a adversarial, yet respectful, relationship between dev and QA where dev tries to get their software released and QA is finding reasons why it shouldn't be released.
If there's only developers who test their own code then they're not incentivized for finding the ways their code breaks. They'll downplay the faults or even be blind to them because they're too close to the implementation and aren't "thinking like a user".
It seems odd to me when those in charge ignore the problems of disbanding QA. But I assume it's because the management may not be incentivized to promote quality software. Instead the incentives are to crank out features.
That said, maybe the market for the software doesn't punish the software makers for having buggy software. In such a case, ignoring QA work is a rational decision.