But if we think prisons are suboptimal, we're more likely to support measures that reduce them.

Suboptimal relative to what. I would prefer replacing them with mote corporal and capital punishment, but somehow I doubt that's what you want. Judging by what you latter wrote, you seem to prefer "replacements" that not only won't help with the problem prisons are designed to solve but create their own problems.

In abolishing prison, we force ourselves to answer the difficult question: How do we provide safety and security for all people?

Yes, it's amazing how any question can be made "difficult" by refusing the answer for no good reason.

In other words, abolishing or severely reducing prisons would force us to come up with other ways to ensure safety, and the author can't imagine one worse than prisons.

See my comment above on corporal punishment. If you abolish not just prisons but all punishment for crimes, then people start taking the law into their own hands. If the law won't punish someone for committing crimes against me, it won't punish me for retaliating.

For what it's worth, the same author wrote https://www.thenation.com/article/abolish-police-instead-lets-have-full-social-economic-and-political-equality/.,

If the title of the article is at all indicative of its contents, the author is an even bigger moron then I thought. Hint: the communists tried instituting full economic equality, didn't turn out so well.

Edit: reading the article it is about as stupid as I expected. For example, the author says:

 However, more frightening than [the shooting itself] is the fact that nearly every night since the shooting there has either been a police car, parked across the street with its lights flashing, or two cops posted outside my building, right at the steps, standing guard.

He never gives a rational reason why this is more frightening, the closest he comes is listing some well publicized incidents of cops shooting blacks (many of which were justified by the actions of the black in question). However, notice that the original shooting occurred in his apartment complex, whereas the police shooting were reported by the media from all over the country. This suggests that the former are much more common and the author is false alieving otherwise due to a media distortion filter.

I was going to go over the rest of the article this way, but now that I think about it, a good exercise for you to improve your rationality would be to go over the rest of this article looking for the remaining fallacies, biases, and idiocies. (It's not a particularly hard exercise.)

and the author can't imagine one worse than prisons

Do you think the author is suffering from a severe lack of imagination or he is lying through his teeth?

An abolitionist framework makes us consider not only reducing mandatory minimums but eliminating them altogether. An abolitionist framework would call for us to decriminalize possession and sale of drugs.

It's interesting that he calls for decriminalization and not for legalisation. Very odd for someone who calls for not focusing on what's politically possible.

In other words, abolishing or severely reducing prisons would force us to come up with other ways to ensure safety, and the author can't imagine one worse than prisons.

The Sharia calls for cutting off hands of thieves instead of putting them in prison. Is the author clueless, doesn't know that and lack imagination or is he in favor of cutting of hands because it's less bad than putting people in prison?

In the context of "given up enforcing".