The SEC is not subject to a ratings agency. It can and will move as it sees fit. I personally do not see an easy resolution to the de-listing problem, which btw affects ALL Chinese-listed co's, large & small. The fundamental problem is the Chinese Gov't .... and, while we're on the subject, they prohibit direct ownership of some types of Chinese businesses by foreign entities ..... which means that if BIDU falls into the pink slips, an investor can't just pull & buy the Chinese shares.
Again, Fitch's rating was on BIDU's debt acquisition, which has nothing to do with U.S. market trading of ADR's.