The C.D.C. guidelines are essentially implying that the risk that the vaccinated will transmit the virus to others, including their unvaccinated children, is so vanishingly low that it is not worth worrying about. But if that’s their position, they should state it clearly and explain it, not just say that “fully vaccinated people have a reduced risk of transmitting” the virus.
I trust Zeynep’s judgement on these matters because she seems to apply informed common sense. My gut says indoor mask mandates should be in place until mid June.