"...this structure had simply passed through the black hole..."
no. not "through" the black hole...maybe through or in the vicinity of the accretion disk which surround the supermassive black hole. the gas cloud likely didn't come close enough to be significantly affected by gravitational tidal effects from the bh.
remember there is no telescope that has a direct line-of-sight view of Sag-A* & the central galactic core region. existing systems pinpoint the location & must still "look" through a thick haze of gases & other various materials.