Open source… a trust certificate or is it really?

The title turned put a lil bit over dramatic then i thought, but basically when a software is open source the general consensus is that its safer the closed, and that there are people who can check the code and see if any manipulations has been done to it … BUT who are those people?
What guarantees that this code is being checked regularly? And that those checkers have the same interests as i have? Nonetheless, checking a code is …

certificate check code general open source people privacy software thought trust