Office-bearers (or “officers” as they are called by Fair Trading in NSW) can or should only issue instructions based on decisions made by the committee or the owners corp in general meeting.
As a member of the committee, you have your say when those decisions are being discussed. If you are outvoted, that’s how democracy works.
However, it is perfectly legitimate for the office-bearers – particularly the secretary – to be the only members allowed to issue instructions. Otherwise you get ordinary members of the committee thinking they have authority to do so when they don’t.
There’s a reason NSW changed the name of the body from “Executive” to “Strata Committee” – some people were a bit above themselves.
Whether or not that applies to your “executives”, only you can say.