Again, you are equating the use of the expressive "rickety" to imply overall bad.
It just could be shaky or inconsistent, which again, he can cover up because he is an elite athlete.
It is all relative, he is still an elite tackle but for a different reason than say Joe Thomas is.
I don't really care to nitpick, because no matter if it is technique or athleticism, he is pretty much elite.
I guess your goal here is to discredit the comments, which honestly you really are not.
It was not even a direct quote by all appearances. It could have simply been the writer's choice of words.