Facebook wasn't entirely silent. They flapped their gums at the start of the project that their stablecoin would be pegged to the US dollar, but would be regulated out of Switzerland.

If it was pegged against the Swiss franc, or against a basket of currencies, they'd have been fine. But they enraged the Americans by trying to have a dollar based coin outside their jurisdiction - and they put pressure on the Swiss and other partners to kill it.

Sometimes the only thing worse than silence is saying the wrong thing.