This parable is unique to Matthew, and I think that understanding that community’s experience helps us see why this one was so important to them. Those who have been uprooted by others (in their passion to be right and to exclude or punish those with whom they set themselves against) suffer.
Those things are not “doing nothing” but in fact call for daily and difficult action - not just feeling merciful but acting in the world in ways that extend God’s mercy to those who suffer. Not just being in favor of peace but taking actions that broker peace, which by definition must be actions that do not mix us up in evildoing. Not just pitying the meek but standing up for them because we hunger and thirst for righteousness.