They claim similarity in that political ties were unilaterally breached, however most people would expect that His Majesty's Loyal Subjects understood the illegality of their actions, whereas the People of the thirteen independent North American States probably had little or no expectation the extent to which the Republicans would go to hold power.
All that is to say that his Majesty's Loyal Subjects knew they would have to shoot their way to independence. The people of the thirteen independent States had already been granted it.
Oh puleeze. Start with reply 204 on this thread and take it from there. Check out the holy trinity of southron thought - Tommy DiLorenzo, Chuck Adams, and the Kennedy boys - and count how many times they refer to the actions of our Founders as 'secession' from the Britain. It's a ridiculous attempt to connect the southron cause with that of the Founding Fathers and it's laughable.