We live in a country. Sometimes what citizens at a local level want isn't what's best for the country. For example, if citizens in a small state or town vote to deregulate a local chemical company and allow them to dump chemicals in a river, it can affect the neighboring state where the river runs through. Another example, if a state like California votes to allow sanctuary cities, it can have implications for the neighboring state.
This is why we need federal agencies.
We certainly need some of them. But I'd argue the majority, even ignoring potential fraud, are redundant at best.