The misnamed "Dark Ages" were actually the Age of Faith and that is resented accordingly by Enlightenment devotees and malignant seculars to this very day. Those who are Catholic and those who love God as Reformed Christians should have no difficulty agreeing on the identification as Age of Faith particularly in the face of nonbelievers who would restrain belief and practice in either group.
It was, indeed, and was not even particularly dark in certain parts. It tended to be in Britain, and so Bede stands out, etc.
It was also an age of those who confessed a Faith, in the particulars, that is identical to those you apparently and routinely mock as 'schismatics'. Yet your distaste for genuine schism does not seem to be shared by His Holiness, who seems to have done everything he can to deny that the Greek Orthodox are schismatic, even to the point of casting doubt on whether The Church, or at least 'new church', this present institutional church, still recognizes the existence of the Eastern Catholic.