What is the significance of the Aveiros listed here?
Rashi: They are all the abominations that the Torah warns about in Parashas Kedoshim.
Radak: They are severe Aveiros that everyone should distance from them, even if the Torah had not warned about them.
What is the significance of disgracing parents?
Malbim (6): A nation can fix its deeds via heeding their parents. Based on nature, children heed them. Here they will not heed them - they disgraced them!
Why is theft said regarding converts?
Radak: All their dealings with converts were with theft, for the convert has no relatives or helpers.
Why does it discuss affliction of orphans and widows?
Radak: They are weak, because their father/husband died.
Malbim: Because people did not fear and honor the Gedolim, they afflicted the weak.