It came to my attention during a discussion not long ago that the context of the phrase may have been lost.
The person I was speaking to, not an American, pointed out the obvious: All men are not created equal. Her example was that the son of a prostitute was not at all equal to the son of a doctor. True, except in one regard; we are all created with unalienable rights given to us by our Creator (see previous post for my use of Creator).
At the time that the Founders proclaimed our independence the civil rights regime of every society that I know of was based on God's direct relationship with the various monarchs extant then. The religion practiced by the monarch did not appear to matter. The structure was always the same.You have heard, I am sure, of the Divine Right of Kings. Further, the rights of his subjects were mostly comprised of the rights he chose to confer on them. For the most part they could be given and taken away at the whim of the monarch. (Until after WWII for example, the Emperor of Japan was believed to be the son of god.) There were some exceptions, the Magna Carta, for example, but not many.
For the first time, as far as I know, the American system disengaged the monarch and put the people, all of them, in direct relationship with their civil rights. The first time, ever.
In this respect, and this respect only, were the Founders asserting the equality of men. This was an incredibly revolutionary assertion.
The then existing institution of slavery does not, in my opinion, invalidate their assertion. At that time those who condoned the practice did not consider slaves human. That they were wrong is beside the point. At that time women were generally not considered the equal of men. That they were wrong is also beside the point.
In their context, in their time, the views they held were commonplace. That they were not as enlightened as we are today is entirely predictable and irrelevant. In case it has gone unnoticed, we evolve. Were it otherwise our creation would have been accompanied by the invention of cars, planes, telephones, modern medicine and personal computers. 10's of billions of us lived and died during the thousands of years that humans were such slaves to our needs and environments that there was no time for meaningful innovation.
When did that state of being change dramatically? The Industrial Revolution and the soon to follow establishment of the United States of America, where all men are created equal and a reliable rule of law, not the whim of monarchs, governs. At the time, the only such place on Earth.