It is a bug in the process, but it's one that has been present (and un-addressed) for more than a quarter century.
When the National Emergencies Act was passed in 1976, it originally said that an emergency would be terminated if each house of Congress voted to do so. Thus a simple majority of both houses was supposed to be able to revoke the emergency.
However, in 1983, the Supreme Court held in INS v. Chadha that Congress couldn't pass laws which gave Congress a "legislative veto" over the President's actions. Thus, any law which included such a provision (like the NEA) lost it.
Without a specific provision in the NEA to create a special type of resolution that didn't need Presidential approval (which was now unconstitutional), it was changed in 1985 to the default "joint resolution" of Congress, which is a resolution passed by both houses and signed by the President, but which doesn't change the law (unlike a bill). This, in turn, means the President can veto it normally, which Congress can then override normally (if it has enough votes).
And yes, to change the law to remove the President's power also requires enough votes to override the veto. It's much easier for Congress to give away power than to reclaim it.