Attachment to the Sunnah grows through reliable learning, practice, and good character. A person must also consider responsibilities and the rights of others when acting on religious guidance. Claiming religious superiority while neglecting family obligations or humiliating people is not sound Prophetic conduct.
The force of فَلَيْسَ مِنِّي should first produce self-examination, not a rush to denounce others. Am I learning sincerely, and am I trying to act on what I understand? Where scholars differ on application, thoughtful consultation is more constructive than assuming that every disagreement is rejection.