Actually, a comma in the opening sentence is perfectly fine. He wrote it in letter format and was addressing it to a particular audience.
The comma before
so is also okay because
so is a conjunction like
but.
A comma used with
and is known as an Oxford Comma and is used to reduce ambiguity.
That being said, the example at the bottom should really use a colon.
Another example:
That is interesting. However, - though this is likely one of those deep-in-the-trenches-of-language sort of thing - to me as a non-English native speaker, the pictures are wrong. It might depend on whether it will be spoken or not. But if you read it out loud, you will emphasize what is needed to avoid ambiguity. To me, reading it to myself, I would not make the mistake suggested. I think the Oxford comma is redundant. So that is the first part of it.
The second part of the picture about strippers is also wrong. Because if the strippers were indeed JFK and Stalin, no comma would be heard. So, no audible break between strippers and Stalin.
Also, in the first part, the first comma makes it clear to me that it is a listing. As such, I know after reading 'strippers, JFK' more listed 'items' might appear. And that strippers and JFK are different from each other, leading me on to understand that it is a varied list.
I think this comes down to reading comprehension and the Oxford comma is based not on ambiguity but on lack of reading skill.
In the second picture you can see how the maker of the picture does not understand the word 'and' very well. He seems to think that the word 'and' connects toast and orange juice to be the same thing, mixed into a mental image of a drink on toast.
But that is illogical thinking that is not a matter of ambiguity. No one in their right mind would see that mental image, so to suggest it would is based on nothing.
It could be an English thing but in my language it would not cause some short circuit in the brain. Because language is not just a formal thing, it is also an understanding of culture. And no one puts orange juice on toast.