The NLRB is the one making the recommendation for a new election, and, since they found that Amazon interfered with the election not just by removing this mater

The NLRB is the one making the recommendation for a new election, and, since they found that Amazon interfered with the election not just by removing this material, but in a number of other ways, why shouldn't they recommend holding a new election? What's the alternative? When corporations violate labor law and interfere with union elections, do nothing about it? More broadly, if Amazon trusted the employees to research and vote of their own volition, why interfere (as determined by the NLRB) at all?