Wrong. Apparently you never bothered to read Philipsburg (Clinton). Only Dunmore's required them to fight.
"John Murray, Earl of Dunmore, Virginia's last royal governor, attempted to do the same thing in November 1775 when he issued a proclamation that granted freedom to any rebel-owned slave who would take up arms for the King."
"Clinton's carefully worded proclamation went much further. Although not once mentioning the word "slave," Clinton "most strictly forbid any Person to sell or claim Right over any NEGROE, the property of a Rebel, who may take Refuge with any part" of the British army. Furthermore, he promised "to every NEGROE Who shall desert the Rebel Standard, full Security to follow within these Lines, any Occupation which he shall think proper."
"In other words, once a slave reached British lines anywhere in North America, his or her status as property ended; no one could claim that he or she belonged to someone else. Also, former slaves did not have to fight in the army to gain freedom; they could do whatever they chose to do. And as British commander-in-chief in America, Clinton's order applied to the entire country as official policy.
“... n that granted freedom to any rebel-owned slave who would take up arms for the King.”
REBEL-OWNED. Again, it did not abolish slavery generally.