I agree with you in theory about how every post should be card related only.
However; discussions sometimes are sloppy and the direction moves away from cards; and then usually returns.
One of my favorite authors, the late David Halberstam, would interweave "distractions" into his books and then use those "distractions" to return to the main subject.
So, let's see how we can compare Mr. Doyle to Mr. Mustin
Rich