I think a point being missed here (particularly in the posts just saying "you pulled it, you tank it") is that "should the healer pull or not" isn't the right question to ask. As other people have already said, first you need to ask whether they were in fact trying to pull in the first place.

Setting a bomb with a long countdown isn't the same thing as running in and directly attacking the enemies to start the fight. That's clearly trying to pull and messing with the tank being able to do their job.

And there isn't enough context in the original post to judge what the exact circumstances were when they did that.

It could have been "too early" and an attempt to force the tank into pulling before the star went off.

Or it could have been cast with a genuine belief that the battle was about to start, and the AST spent the next twenty seconds panicking because nobody had moved and there was no way they could deactivate the star.

Just responding to the basic question "should the healer pull?" isn't a fair discussion of this specific situation.