When I saw the title of this thread I knew exactly what it would be about.
Neither decision did me any favour and I can just about see the argument for the Stewards' decisions. R6 the
could have placed higher and so the interference did "cost him a
chance of a higher placing". In R8 the
ran on to finish ahead of his near rivals after interference yet many length short of the leading bunch and in my opinion probably was not cost a place. I rated the R6 5/10 chance of a DQ and R8 4/10 after watching the replays and before the stewards decisions.
There is a bigger issue of consistency across tracks. There are some tracks where they almost certainly would have both come down, and some tracks where probably neither would have.