Also, the standoff in space made no fucking sense. And what the fuck was the point of the bright beacon thing? It's not like a light signal is going to reach Qo'nos or some shit. Just seemed arbitrary and dumb, like, couldn't they have simply said, "sir, we're detecting a transmission directed at their home world, I expect they're summoning backup". Would have made just as much sense.
You'll remember that not only was it bright, it was blaring a subspace signal too and those would make it to Qo'nos since that's how you communicate FTL in Trek. The more unrealistic thing in the Trekverse is that they shouldn't have been able to assemble that many ships that quickly on the outskirts of Federation/Klingon territory especially since the Captain mentioned they were the only ship for at least 6 light years.
The Klingons on the ship even had an argument basically,
"I find great wisdom in your teachings, -but- can you be sure our brothers and sisters will answer your call?"
"They will because the prophecy commands all Klingons must come to the light of Kahless when it shines in the night sky."
"Will ships really fly across the galaxy because of a fable?"
...
So basically it's Klingons being loosey goosey with their religion just like they did on the episode of TNG when the Klingon priests cloned Kahless to unite the empire. It has to be bright and loud because the legend says that it's essentially a star that appears which calls the Klingons to assemble.