‘They answered and said to him, “You were totally born in sins, and will you try to teach us?” And they threw him out.'
They had no answer to his logic, and so, as such men will when they will not admit that they are wrong, they attacked the man and took action against him. They threw him out. This may simply mean that they forcibly ejected him, or, more likely, that they officially excluded him from synagogue worship.
‘Born in sins'. This reflects their general view, a view which Jesus had combated earlier, that his blindness was due to someone's sin, probably his own. An interesting example of later Rabbinic thinking on this is found in Midrash Rabbah on Song of Songs 1:41 which states that when a pregnant woman worships in a heathen temple the seed within her also commits idolatry. Their prejudice convinced them that this man too was unworthy for some similar reason. He has borne the mark of sinfulness upon him, how dare he criticise them?