"The fastest boat always wins ..."The OCS is not relevant. It happened after, and it doesn't apply anyway.
Seems fantastical to assume anyone would know whether that INEOS tack in that situation was slower than normal or not.
LR didn't tack to port. So that is hypothetical and you would have to provide more detail than is possible to provide for a clear judgement.
No, it's not OK to hit another boat in these races. It's not dinghy team racing.
Probably that exact situation won't happen again. Hopefully the boats learn that they can't slow down so they shouldn't be early. That's the low hanging fruit.
If you are confident in your speed then there is absolutely no need to mix it up in the pre-start (until it gets to races 8 and 9 in Bermuda and you're finally allowed some wiggle room to cut loose and show true form - just to make a statement).
I might be wrong.