Burke was considered quite the scholar on Matrimonial law after he published his dissertation in 1986, arguing that mental "deficiencies" (specifically schizophrenia) were an impediment to the sacrament. It would be interesting to consult a canonist, but it seems that he holds the view that there are specific, defined impediments to contracting Matrimony, and specific processes for litigating those impediments, outside of which there can be no remedy -- especially what Pope Francis calls a pastoral remedy -- precisely because there are no defined criteria unless there is a formal process. 

I think the whole business is Byzantine (apologies to the Byzantines in our midst), but it appears Burke sublimates the pastoral to the juridical -- which, unfortunately, is what Canon Law has done for many centuries.