It was my understanding the the tankers could not be insured or it was prohibitively high cost without the margin cost covered and therefore could not pass through.

https://www.spglobal.com/energy/en/news-research/latest-news...

Either way for sure this will cause further backlog. And for what.

These particular ships technically were not attempting to pass through the strait, they were anchored in Iraqi territorial waters. The backlog will extend even further now that it can be considered risky to be anywhere near the strait.

some of them were not in the straights just near.