I hope so. I think it's worth working on ways to reduce the probability and severity of this attack. So, in an academic sense, it's well worth worrying about. But it would be really odd to argue that people should avoid Bitcoin because of the very small risk of this kind of attack.

In addition, though the known solutions (at least known to me) to a 51% attack (from a motivated attacker with significant resources) are pretty awful, it's not necessarily the total death of Bitcoin. So while it would be a severe blow (as the block chain split was, as the recent price crash was), I would expect Bitcoin would survive somehow. Bitcoin's death has been predicted so many times and Bitcoin has weathered crises.