The problem with that, and you don't seem to have noticed, is that in every game I've played no matter his alignment nobody finds Mez scummy like ever. (Occasionally me and storm but that's it) So I wasn't about to change my mind based on that.
The me being less wrong is solely on that no one lynching Yiga expected to get the slightest bit of information amount out of it whether he was scum or not.
I've definitely found Mezlo scummy before, but I don't think you should default to thinking he's scummy just because no one else seems to question him.
Also, you never did quite state why you thought Mezlo's lynch would give us more information than Yiga's?