All data in Bitcoin is arbitrary. It is also precisely bounded such that it has a limited growth rate. It is a matter of opinion which parts of Bitcoin are "good" and which ones are "bad." It's a matter of insanity to think you can get rid of the bad stuff without destroying the good stuff, because they're all valid transactions. And all valid transactions have to remain valid forever. So yes, I think some of that stuff is garbage. But I'm also not insane enough to think you can remove it at a consensus level. Nodes can prune the chain already to make it easier to run. Literally none of the anti-spam arguments survive contact with the real world.