Here is what Owen Chadwick says about Table Talk in his book The Reformation, p.74-75
The characteristic memory of Luther is of a man presiding at his own table, with is his colleagues and friends around, arguing with him, or listening to his divinity, his politics and his humour, One of the friends shamefacedly took out a notebook and began to jot down Luther's remarks. The habit spread, and twelve different reporters made collections. Luther sometimes mocked nut neither resented nor forbade these deferential scribes. Twenty years after his death, one of them, Aurifaber, published a collection from a variety of collections . Thenceforth Luther's Table Talk became a classic of the Reformation. Rude and outspoken he might often be; 'Dear husband', said Catherine, 'you are too rude'. 'They teach me to be rude" replied Luther. He was so outspoken that his enemiesleaped to make capital out of the Table Talk. It is unreliable as a source for details of history, particularly when the events occured many years before the date of the reported conversation; and Aurifaber's text was not untouched by improvement or interpolation. But iit is a unique and authentic picture of a man and a divine; he who would understand Luther's person and mind cannot neglect it. It is impossible to apply any epithet to him less than the old classical epithet magnanimous, in its original sense of great-hearted.
I observe that Lutherans are not bothered at all by the assasination of character hurled at Luther, primarily because they are not bound by what Luther said, they are bound by what is in their confession, though some of it were written by him. For after all - Luther himself was both iustus et pecator, just like any other Christian, hence he is treated like any other Church Father, capable of error, respected but no idol.
1And I, when I came to you, brothers,[a] did not come proclaiming to you the testimony[b] of God with lofty speech or wisdom. 2For I decided to know nothing among you except Jesus Christ and him crucified. 3And I was with you in weakness and in fear and much trembling, 4and my speech and my message were not in plausible words of wisdom, but in demonstration of the Spirit and of power, 5that your faith might not rest in the wisdom of men but in the power of God. - 1 Cor 2