When Russia announced that they were going to build a causeway and bridge across the strait, before they even broke ground, Ukraine swore they'd blow up portions of it. Given that fact, Russia didn't change any rules, they just put a couple of small ships in the area to patrol both sides of the causeway. They also instituted patrols that travel back and forth across the bridge looking for small boats and divers in the waters around the causeway.
The three ships that were stopped are the first ones from Ukraine that didn't obey the rules. Given the fact that a very small lighter carrying supplies to a Burke class destroyer blew the destroyer nearly in half, any country concerned about attacks on a ship, bridge, or causeway, would have done the same thing Russia did which is stop any vessel that has not followed the rules and refused to halt or even respond to radio inquires from the Russian patrol vessels.
Be careful about your double standards.
It’s rare when facts matter in conflicts of passion.
Those who passionately hate Russia will see nothing but the Ukrainian claims of innocence and Russian belligerence.
The history of Ukrainian pledges to blow up the bridge will not be considered, nor will the break from established protocol by Ukraine give them pause.