Palantir famously sued the army and won, now accounting for the majority of their USG revenue. So, this is not necessarily a bad strategy.
Key differentiator though is Palantir’s suit was based primarily on Congressional acts and explicit clauses of the FAR. This absolutely does not seem to be the case for Anthropic, who could easily do the same, but chooses another ideological battle. I can’t imagine their legal counsel would recommend this route (actually asking Claude it doesn’t either!) which would imply this is Anthropic leadership’s move.
I’d gamble they’ve already given up on actual business with the government/military and that this is more of a PR move to further distance themselves and maintain a high road image.