go look up what other illegal union busting behaviors they've gotten away with. and look at democrat or republican behaviors, such as biden actively strike-busting the other day
strike busting public unions is good. we should never recognize public unions. there is no middleman to reduce profits with the government, higher wages means we pay more, there's no "evil capitalist" who will get less instead.
An alternative perspective to look at this is that orgs like USPS are services provided to Americans because they're the kind of services that would otherwise be inaccessible to great majority of Americans. For this reason, increasing the wages and potentially attracting better workers and increasing the morale (and thus performance) of existing workers are beneficial for Americans.