Not sure what this is

Can someone help out with this: the first one seems wonky and so does the second one!

"Not all headsets are created equal"

"Not all headsets are created equally"

It's a common phrase (the top one), but why does it seem wrong?

Which is correct?!


First off, understand that it is a play on "All men are created equal", from the US Declaration of Independence.

But, aside from that, the meaning of "equally", in the same context, would be ambiguous -- does it mean "created with equivalent status" or "created with equivalent resources"?