I think IA is already overloaded as-is. I know it's hard to keep that insane amount of storage available but it's still always slow. They probably only have one server location, as opposed to a global CDN like YouTube.
Their goal is to make everything available, not necessarily available quickly; people going to an archive are generally looking for something in particular so a bit of latency doesn't really affect the majority of valid use cases. They're not hosting a CDN and they want to discourage people from treating it as such. It also puts off scrapers as I imagine the rate at which you could scrape is slower than the rate at which content is added to the archive
I know. I'm not saying I need it any faster and most people in fact don't, but as they have no incentive to widen their bandwidth, we can expect outages if they ever make some lawless group angry.
I'm more cynical, I think it's just for clout and marketing. IA is widely known and used, so an attack is guaranteed to be noticed and generate news articles. They're also known for having large robust infrastructure, but they aren't large enough that an attack is impossible, so a successful attack is impressive yet still feasible. If someone can pull it off, it would make great marketing for their black market DDOS service and also grant huge bragging rights in certain communities.
IA is one of those rare organizations that have an incredible online reach and notoriety but aren't backed by a trillion dollar corporation. Taking them down is easier compared to other sites with the same amounts of traffic, while still providing a lot of publicity. Another example would be Wikipedia, however most of their content is plain HTML and easily cacheable too. The IA has a lot of heavy media; videos, old software, photo's, etc not even mentioning the ability search over all those millions of pieces of content. It seems like a prime target for this kind of pubilicty stunt.
Look at every dictatorship. Look at extremism. Look at wife beaters ffs. If someone is trying to DDOS the Internet Archive then someone is trying to mess with the free flow of information.
That's not a sandwich, it's a sub. A sandwich is made from sliced bread, not from a bun. That's why a sausage sanga is a sandwich but a hot dog isn't. Hot dog has a bun, disqualifying it.