The 3 strikes rule is indeed a problem, but besides that the parent still has a point. A lot of the low-value robberies involve threats or violence, where as high-value art thefts pretty much never do.
What's worse, Nuisance crime or high impact crime? Do we come down on the fellow who stole a Twix bar for the n-th time or do we lock up the guy who proved that we really need million-dollar locks and alarms for the library holdings?
To play devils advocate, part of the purpose of prison is to shield society from people who are particularly damaging to society. Repeat offenders have shown that even after being given repeated negative reenforcement, they will still carry out activities damaging to society.
I'm not sure life in prison is the answer, but it does make sense that repeated aggressions would be met with stronger negative feedback.
Stealing culturally significant items from the public like this case is more similar to graft or corruption, or breach of fiduciary duty. White collar crime. Far from victimless, it hurts everyone.
I think the main reason the US throws people in prison for extended periods for petty crimes is if those crimes were repeat offences - so you have ridiculous situations where people serve years behind bars for stealing toothpaste.
This case is kind of odd though, as the perpetrator committed the same crime many times over a quarter of a century. The items stolen were also of great cultural value. So here we have a person who has repeatedly stolen cultural items, yet they get a very lenient sentence - I very much doubt the sentence would have been the same had he been a black man from a working class family.
This case really highlights the two-tier legal system that exists in the US.
While the parent is correct that the person robbing a store is very likely using a weapon to do it, they left out that the US uses a rather extreme increasing punishment system for repeat offenders.
People robbing stores, I'd wager, are often repeat offenders. Mandatory minimum sentencing laws over the last few decades have dramatically increased the prison-time durations for those people, even for many lesser/low violence crimes.
it's usually because the bodega thief is waving a gun around and threatening to kill someone, while the library thief isn't.