Can a comma "improperly" join two independent clauses?

[Imperio]

As far as I could tell, joining two independent clauses with a comma is grammatically correct and simply up to personal style. For example, according to the words of Scott on this forum, it is correct to write, "I went to the kitchen, and I ate pizza." If one chooses not to use a comma, it is equally correct to write, "I went to the kitchen. I ate pizza."

So then, could someone please explain to me how it is incorrect to use a comma to separate two independent clauses in this sentence: "It was genuinely interesting to learn about the lives of these historical figures, and having finished this book, I appreciate this unique touch." This matter with commas is all so confusing. I was told in a review of mine that this was incorrect.

I appreciate any further elaboration anyone could bring! Maybe it will help others whose thoughts have never truly been verified about this matter involving commas too.

[MrsCatInTheHat]

With two short clauses, as in your example in paragraph 1, a comma could work stylistically. If one or more of the clauses is longer, a semi-colon would be needed. When in doubt, use the semi-colon. In your second example, I would have skipped the interrupter and used a semi-colon after "figures." Oftentimes, I find that interrupters reduce clarity when they should increase it.

[Helen Akoth]

As far as I could tell, joining two independent clauses with a comma is grammatically correct and simply up to personal style. For example, according to the words of Scott on this forum, it is correct to write, "I went to the kitchen, and I ate pizza." If one chooses not to use a comma, it is equally correct to write, "I went to the kitchen. I ate pizza."

So then, could someone please explain to me how it is incorrect to use a comma to separate two independent clauses in this sentence: "It was genuinely interesting to learn about the lives of these historical figures, and having finished this book, I appreciate this unique touch." This matter with commas is all so confusing. I was told in a review of mine that this was incorrect.

I appreciate any further elaboration anyone could bring! Maybe it will help others whose thoughts have never truly been verified about this matter involving commas too.

I share your sentiments @Imperio, and I believe there is nothing wrong with your sentence. The sentence ("It was genuinely interesting to learn about the lives of these historical figures, and having finished this book, I appreciate this unique touch.") is grammatically very correct. The only time a comma can improperly join two independent clauses is when you use a comma but fail to include a coordinating conjunction, something that results into a comma splice. But when you use a comma together with a coordinating conjunction in joining two independent clauses, then that should not be considered an error.

[Samuel Mamo]

It was genuinely interesting to learn about the lives of these historical figures, and having finished this book, I appreciate this unique touch."
I do not think there is an error. But would be better if you put full stop or semi colon after "figures".

[Leonie Vermaak]

My suggestion would also be to put a full stop after 'figures'. Another thing you might consider, is to take out the part 'and having finished this book' as it's an unnecessary statement, due to the fact that a person can only do a review once you have finished the book.