That’s true in the https://en.wikipedia.org/wiki/Cataphatic_theology
but not true in the
https://en.wikipedia.org/wiki/Apophatic_theology
or negative theology (describing God only by what God is not).
It’s likely that Hume was unaware of apophatic theology as it’s not part of the Catholic -> Protestant -> Rationalist -> Atheist tradition but rather part of the Eastern Orthodox Christian (middle eastern, not far eastern, although they had forays there too) theology.