Why were many colonists opposed to the Proclamation Line of 1763?

The main reason why colonists were opposed to the Proclamation Line of 1763 was because the Seven Years War (French and Indian War in the United States, 1754-1763) put the British treasury in dire straits and King George the III needed all the revenue possible from his colonists. From his way of thinking, the further the colonists migrated west, the less dependent upon British trade (and their paying taxes) they would become as they became increasingly more self-sufficient. King George and his First Lord of the Treasury George Grenville believed that the American Colonists should have paid a greater share of the cost of the French and Indian War, and thereby began imposing more and more taxes and "reforms," sowing the seeds that sprouted into a War for Independence in the following decade. But the colonists wanted the freedom to go west to the rich and fertile Genesee River Valley and Western New York, the gateway to the Allegheny - Ohio River system and the way further west. (Remember, north of the Fingerlakes was impassable and a virtual swamp, until drained by the Erie Canal in 1820.) The best way west was up the Susquehanna River, across Allegany County to the Allegeheny River, and then all the way to the Mississippi. The Appalachian Mountains, then called the Allegany Mountains, were an effective geographical fence for King George, except for the passage through Allegany County. And the Proclamation of 1763 was an effective geo-political "gate" blocking the "hole in the fence" of the mountains and thwarting the colonists dreams and desires to immediately claim and settle the fertile and vast land of the Seneca (westernmost tribe of the Iroquois.)