No. Bureaucracies are instituted by the legislative branch which chooses to delegate governmental powers (eg rulemaking) to them for the sake of efficiency, usually under the direct or indirect supervision of the executive branch. They don't spring into existence fully formed, and while professional bureaucrats certainly feather their nests and try to grow their empires, legislators are ultimately responsible. Many of them like using public institutions as straw opponents to impress the credulous.

Unelected bureaucracies absolutely dilute the efficiency of democracy, some times grinding it to an absolute halt. If this weren’t true then you’d never see disputes between bureaucrats and elected executives, but you do see that, all over the world. Some commonwealth countries have it even worse, where certain government institutions are accountable only to the king, rather than any elected executive authority.