The players(collectively) have an enrage timer.

[Amiaze]

But there is no need to swear and scream as if the player did kill someone dear to them,

Regardless of that today we did the same boss (2nd boss in Fractal) and this friend did interact with those glass tube to summon the add.

Oh, no, there's never an excuse for that. It's frustrating when you die, yes, especially when it's because people chose to ignore mechanics. But I've found that parties in which people begin to swear at you are the parties that won't perform well at all. Everybody's in a bad mood because of the hostility, and they under perform.

One or two people spoiling an entire run is definitely sad. My enrage was always Scylla. People never understood that different alliance received different numbers of ice/fire balls that needed to be shared amongst the entire group.