I appreciate your effort to clarify your motivation for making the change you made. Your stance seems to be that my way of mapping this feature is incorrect. The argument is that a tidal water body cannot be a closed loop of coastline separate from the ocean because the tidal influence would then not reach the waterbody in question.

I see where you're coming from, but I respectfully disagree. Tidal influence and seawater can be transmitted by way of mechanisms that we usually map as land, as opposed to water in OSM. I can think of at least three general examples:
- A culvert
- A natural arch
- A permeable embankment, like in this case.

In light of these counter examples I don't think I can lay weight to your argument.

I'd be persuaded if the community has discussed edge cased like this extensively in the past and arrived at a strong consensus on how to map them, but I struggle to find any documentation pointing to this having happened. I'd be grateful for your help in searching.

Although I think you have good intentions, the fact remains that you are unilaterally harming my (in my view perfectly valid) mapping. The bar for doing so should usually be very high. You personally disagreeing with my mapping style does not cut it.

Hence, I will probably revert your change again if nothing new comes to light in this conversation.