They have a court ruling ...
... that makes a clean room implementation copyright infringement unless it is somehow shown to be fair use.
Not in this case, surely? The lower courts ruled/juries dismissed Google's fair use claim based on their admission to copying for convenience, not that they'd done a CRI. If you're referring to another case with judgement for Oracle, please cite.
If 'fair use' even with copying for interop turns out to be legally cloudy/high risk after this case, there's a longer term win all 'round, where open standards set by foundations/industry bodies/standards orgs are in the ascendant due to cost / risk factors, rather than vendor proprietary, monopoly solutions (even if freely provided, for now).