Do speaker cables need a burn in period?

Again, I am in neither camp on this burn-in issue, so I can somewhat objectively tell you that both sides seem entrenched in the same way. Same pattern with different prefix. If you have a firm belief in existence of burn-in, arguing with someone who has a firm belief in its non-existence will lead you nowhere, except for frustration. The only ones you could try to explain your views to are those with no loyalty to either camp. However, you may need to accept their doubts and questions as legitimate, too. So far, most of the burn-in proponents answers to challenging questions have been "it is that way, you just do not get it, shame on you" kind. Who would go for that?

Seems like the non believers care more about being eloquent than being logical.

Fine, frame a syllogism that rationally supports your views, free from rancor or sophistry. We shall go from there. 🐈💩

That's the problem with lawyers.  They care more about confusing with subjectives than the truth.