Republicans have objected to infrastructure bill from Democrats, even though it contained same things they previously wanted to fund.
Just because they didn't want to give Democrats a "win". Now they want to drive out of office fellow Republicans who supported the bill.
All that really matters to either party is that their candidates have power. Neither it interested in the good of the American public. Each has some platform items, be it "National Defense", "Environment", or "Eliminating Discrimination on the basis of Race"
In some cases the party has, how shall I put this delicately? "Revised their position" compared to where they stood originally.