We have three branches of government that are at least theoretically coequal and restrained by the constitution and bill of rights.
Then we have the regulatory agencies which are a law unto themselves. There is no bill of rights to protect you from them. The other three branches have set it up this way and are complicit in keeping it this way. It gives them a way around the constitution and gives them complete deniability.
If congress passes a law you have all kinds of noise surrounding it. You can take it to court, you can vote out the people who passed it if you don’t like it. If an agency writes a regulation, it has the force of law and there is no recourse. Take it to court? Sure, fine. They have lawyers too and an unlimited budget for litigation.
That has already happened. In 2007 SCOTUS ruled that CO2 was a pollutant, that EPA should determine the threat of CO2 and if needed regulate with the Clean Air Act.
First Bush, then Obama deferred to Congress to step up, but Congress couldn't.
Now, we are in the 2nd wave of court action. Were EPA's endangerment findings accurate and does EPA have the authority to "tailor the regulation"? The DC court of Appeals said yes, and now SCOTUS will have to rule on those questions.