They had a whole new PR plan, compared to ComStar: they went in & helped people. Particularly in the Chaos March.
They rooted out bandits, castigated mercs for keeping conflicts going in their own interest. They did rescue work, they built schools, they set up hospitals. They backed idealistic local politicians, and never actually themselves had to say "Look at what your Successor Lords haven't been doing for you" - enough locals said it for them.
They backed regimes with funds, equipment, and advisors. The Word gave them all the best help! With WoB acolytes managing the commnet, the hospitals, and working closely with the security forces, the common people were getting peace and services like they'd never gotten before.
And remember - 95%-99% of the WoB people were not the lunatic fringe. Most of them honestly thought they were the organisation they said they were. And most of them didn't understand why all the corrupt Houses declared war on them, but were determined to preserve the good work they'd done.
At first, anyway.