“It is the Protestant belief that the Bible is the only source for teaching on doctrine and morality.”
When you get the very first point wrong, then how much hope is there for the rest of the article?
Maybe if you want to know what Sola Scriptura is about, you might want to try asking a Protestant? Catholics around here love to complain that Protestants assume things wrongly about their beliefs, and then they post articles like this which do the same thing.
What does Sola Scriptura mean?