I see no reason a dliner should have good blocking stats. Yet they all do. Do they use it for anything or is a glitch in the character creation systrm

You are seeing a combination of things, I think. One is lots of those players have had money spent on them and then auto-trained. Another is D line are useful on sp. teams so they need to block and tackle. And then again there are some who believe that blocking will help D line defeat blocks. You will have to form your own opinion on that one because all my sp. teams players block but I have not seen evidence they are defeating blocks at a higher rate.