Aliens are those who have not yet become denizens.
There should be no confusion on your part. The English-born children of aliens DO NOT have the same privileges as English-born children of English subjects. That's why Blackstone deliberately used the disclaimer, "generally speaking."
If they were the same, there would be no need for the disclaimer Blackstone used.
Blackstone IS very clear:
“But this opinion has been since overruled:52 and it is now held for law, that the sons of an alien, born here, may inherit to each other. ...IT is also enacted, by the statute II & 12 W III. c. 6. that all persons, being natural-born subjects of the king, may inherit and make their titles by descent from any of their ancestors lineal or collateral; although their father, or mother, or other ancestor, by, from, through, or under whom they derive their pedigrees, were born out of the king’s allegiance.”
If a denizen died, the property he had would go to a son born after the denization. If a son had been born in the UK prior to denization, that son was a NBS and could inherit from anyone. But a son who was not a NBS, and who was born before denization, was not eligible.
You cannot take a sentence fragment out of context and then proclaim yourself an expert in British law. You actually have to read whole sentences, and maybe even paragraphs. To fully appreciate it, you would have to study for years.
Blackstone wasn’t a blowhard. He was an expert. But even with Blackstone, you can’t take a sentence fragment and declare victory.