This is a great example of why it’s so important to address freedom of movement at all times. Unaddressed, it leads to further illegal acts and rough play. Here the first illegal act is Tatum holding Durant as Kevin is trying to cut. After that illegal action goes uncalled, Durant commits the second illegal act when he pushes off Tatum. A foul was needed at the start of this sequence on Tatum. Had it been called, the second act never happens. A whistle was definitely needed on this play.
Boston Celtics at Brooklyn Nets | May 22, 2021 | Freedom of Movement
I. GUIDES FOR ADMINISTRATION AND APPLICATION OF THE RULES
Each official should have a definite and clear conception of their overall responsibilities. It is essential for them to know, understand and implement the rules as intended. If all officials possess the same conception there will be a guaranteed uniformity in the administration of all contests.
The restrictions placed upon the player by the rules are intended to create a balance of play, equal opportunity for the defense and the offense, provide reasonable safety and protection for all players and emphasize cleverness and skill without unduly limiting freedom of action of player or team.
The purpose of penalties is to compensate a player who has been placed at a disadvantage through an illegal act of an opponent and to restrain players from committing acts which, if ignored, might lead to roughness even though they do not affect the immediate play.See Rule