Why are commas needed in the following sentences?
Solution 1:
All the commas you noted are a stylistic preference. In my own writing, I'd probably omit them.
Solution 2:
In all the cases above, the commas set off supplementary information. It can be added, almost as an afterthought, or removed. In the first two cases, the comma is, I would argue, optional. You can certainly find many analogous cases in edited, published material where it is omitted. In the last cases, the supplement, coming as it does between the verb and the object, presents a stronger case for commas. Commas, though, are often as much a matter of style as of rules. As Adam Freedman has said, "In the 18th century, punctuation marks were as common as medicinal leeches and just about as scientific." To think that we've now made them entirely scientific would be naive.