Technology

Not "clearly" at all. It could be as simple as someone new to coding doing it accidentally, probably using masking of their request origins (granted, this does not seem very likely at all...:-D).

Also, it forces the archive to expend resources that they could have allocated elsewhere - which would have longer-term consequences far beyond the short-term duration of the attack. Enough attacks like these could cause the archive to deprioritize something else that they had wanted to do, or drop something they used to support but won't be able to continue to do so in that case.

Or, why does a bully hit someone? That too offers purely short-term pain, until the next attack. Yet they do it anyway, and often it works to cow the victim into submission so that future attacks aren't even necessary, and instead the mere threat of one may be sufficient for the bully to get their way.

Also, does the entire rest of the world submit funding to the internet archive? I don't know anything about their finances, but compared to those of e.g. Russian disinformation sources or corporate profit-seeking, surely they are tiny in comparison?

The only thing "clear" here is that the attacker seems to be using the Might Is Right principle, as they are stepping outside the bounds of society to take on this vigilante effort by themselves.