In fairness to MAG, I can't recall any instance of them objecting to financial support for competing airports. And prior to the pandemic - which was exceptional for the entire industry - the local authorities in Greater Manchester routinely budgeted for receipt of a substantial annual dividend from MAG which they then used to pay for council commitments. The airport operator provided financial support to the local authority owners, not the other way around.
MAG did receive funds during the pandemic, but they will be expected to repay these as business recovers back to normal levels, and the owners will doubtless look forward to a resumption of generous dividend payments down the line.