Hard disagree. The ATC initially cleared them to cross the runway. The truck started moving, and just then the ATC realised that they made a mistake and tried to fix it. Even their first attempt at that was unclear, and they only clarified who should stop on the second attempt.
People can’t react in zero second, trucks don’t stop immediately. The ATC mistake was clearing them to cross the runway, whatever happened after was out of their hands.
Controller probably should've told them to expedite the crossing or warned that traffic was about to land, but they were managing a lot at once; tower+ground by themselves and an emergency already.
Doing it at LaGuardia or any major airport is absolutely nuts.
Add a few seconds for human reaction time on both ends, I don't think that's really "enough time to cross safely" - maybe if the stars align.