The pensions covered by the arp money are pensions offered by private employers that have failed. I'm not aware of pbgc covering govt pensions. The businesses you are so fond of guaranteed things they could not make good on. Even when most of these workers were paying insurance to further guarantee the pension. The unions didn't unilaterally impose these pensions. The EMPLOYER presumably agreed to the deal and agreed to fund the deal.
So its a business bailout too, how many effing times are we going to bail out things like airlines who keep taking the bailout and pissing them away and providing shtt service?
People are tired of privatizing the gains and THEN socializing the losses.
The sad part about this whole thing is that many of the people who will get the ARP PBGC bailouts are the blue collar Trumpers who will turn right back around (after quietly thanking God for Biden) and vote for whatever Trumpy hack is making jokes about "libs".