Well, I certainly don't see how burning the protein would make it more suitable for assimilation, I think it's a myth that's just been repeated without any evidence, if there is any I'm interested in hearing it, intuitively it doesn't make sense.

Fermentation & aging by bacteria on the other hand does breakdown meat and eases digestion, and it's a tradition all cultures have kept in some form, as evidenced by numerous dishes still consumed today.

"Burning" may not be the right word. Denaturing (i.e., the proteins losing their quaternary structure) may be what increases bio-availability