Having read Francis Pryor's book "Seahenge", which deals not just with that monument, but with a host of other important sites around the north fens area, and having watched the Time Team episode on Seahenge, and having read numerous news articles representing all sides of the argument, I have the following opinions to add, so here's my two-penneth:-
Please will you all treat me kindly, as this is how I see it, and not in an arrogant way, or in a way dismissive of anyone else's opinions.
Firstly: Seahenge was saved from destruction from coastal erosion. Nothing can prevent that. It could have been left in situ for everyone to see, or it could have been excavated and removed for archaeological analysis, and for preservation for generations to come to look at. Leaving it in situ would inevitably have resulted in its destruction, or even its robbery by souvenir hunters (after all it was only wood, so easy to take home), therefore leaving nothing for people of the future to see. Also, its removal enabled us to understand it more.
Secondly: Francis Pryor, who didn't personally excavete Seahenge, excavated a lot of very significant sites elsewhere in the Fens, most of which were done because a gravel-extraction company were wanting to do their bit, and were most co-operative in letting the excavations take place before they set to work. We could argue that those sites, previously undetected without pre-industrial excavations, should have been left alone too. Is it only the sites that are made visible that matter? However, those sites, once exposed, would have soon decayed, like preserved wood in peat does, once exposed.
Thirdly: No-one has any right to archaeological sites, in terms of religion, as we don't fully understand the religion of those people of so long ago, so the Druids who tried to stop the site being excavated were presuming it was a Druidical site. Druidism has only been documented from a much later date, so they can't make any realistic claim to the site.
As far as I understand, no singular religion has a real claim to any prehistoric site, but we all feel we have a reasonable opinion on it. Do we really?
To finish: We all have strong feelings about things we care about in our lives, and prehistoric sites are one we, fortunately, all share.
I can understand the frustration felt by people of all opinions, especially when I say again that no-one has a claim to the site, as it has nothing to do with any of us personally, or us as a nation. It was built by people a long time ago, who had a different outlook on a different World to ours, so how can we even try to claim, or pretend, we know about what it meant?
The Seahenge sage was about trying to save something precious from damage, and, ultimately, destruction. The sea cannot be stopped so easily. After all, it was the sea that revealed it in the first place, and it would have been destroyed by those same processes.