That political party's actions are about weakening the federal government so as to make it easier for large corporations to behave abusively, not because of trust. States have less resources, and can be played against each other.

The public-facing excuse for Joe Q Public is "they can't be trusted!", "less taxes on your hard-earned money" (when corporate share of taxes has plunged from the 50-50 split it used to be, increasing individual taxes), "the government is not efficient" (usually because of lots of onerous regulations and reporting and oversight that, ahem, a certain political party insisted on to fight "abuse")