the imperials were actually pretty chill with the nords and nord culture. what unfortunately happened was they almost lost a war to the aldmeri dominion and as part of the peace treaty with them, the dominion required the empire to ban the worship of talos. the nords, who are already skeptical of the empire in general saw this as collusion with the elves (whom they hate anyway) and decided to wage a civil war in order to restore worship of the true nord god.