This does not change that in the least. What changes is that if e.g. the FDA is acting in a way that does not seem to fall within their legal mandate, then people have more freedom to take legal action to ensure they fall back to within that mandate. And I think this is extremely important. The United States it not a dictatorship. People should have the right to challenge organizations which seem to be going beyond (or even against) their legal mandate.

If Congress is unhappy with how this plays out, they're completely free to clarify any sections that get challenged.