The majority of people thought they were voting for cheaper groceries, not for undoing our entire system of alliances and global trade.

Also, the President is not a King, so just because people voted for him it doesn't mean opposition ceases to exist. Opposition and push-back to executive policy been a mainstay of US politics. It's been true of Democratic Presidents (e.g., federal courts blocking Biden's policies), and it remains true of the current President.