I felt like I was going crazy sometimes with how often people in the FOSS community insist that nothing is wrong when large companies are massively profiting off of unpaid labor that is meant to help people

Starting a project as just source-available or with noncommercial clause is just fine. But the definition of free software and open source are pretty unambiguous - software with noncommercial clause can't be either. The problem really happens when certain companies/projects want the advantages of the FOSS label, but don't want to make the compromises associated. Any FOSS project has certain advantages that comes with the label - promotion by individuals and industries, widespread training and external contributions. Some companies/projects start off as FOSS (almost always with CLA) and take advantage of all those. Then when they're popular, they switch to non-commercial, citing competition. Hashicorp and Redis are examples of these. When they cite unfair competition, they're outright denying the contributions of external players like contributors and industry that popularized it. It's basically a rug pull.

Another form of this is a recent trend of people claiming that non-commercial clauses count as FOSS. I've heard weird claims like the FSF and OSI don't a monopoly on the definition of what's FS or OSS. Yet others simply ignore these definitions. Any project that wants to be source-available should compete on their own merit, rather than riding and exploiting the world's preference for FOSS.

I think that non-commercial-use clauses are a good way forward for certain projects, and commercial licenses for others.

Just want to reiterate - it's ok as long as it starts as such, instead of doing a bait and switch. But another method is to use AGPL or similar license for all your code. The corporations that exploit FOSS code hate this license. And that's why they widely promote the idea that copyleft licenses are less-free compared to permissive licenses (less free for them to exploit, perhaps). Unfortunately, many FOSS developers have bought this BS.

by turning it into part of their closed-source product

Corporations convert a lot of FOSS code into part of their closed source products. Using copyleft instead of permissive license is a good way to prevent that. But that aside, there is one class of software whose exploitation can't be solved with copyleft licenses - cloud software. Many companies that switched licenses were offering cloud services. And then AWS of GCP comes and offers their cloud version, forcing the smaller companies to go source-available. The main problem I see is, why are they cloud software? The main goal of free software is freedom - especially the freedom to privacy, to own the data and to decide on the computation. That's much better served on local machines than on the 'cloud'. That's much easier today with machines that are magnitudes of order more advanced than a decade old ones in terms of computational power and storage. Yet, we see companies wanting to turn all that computing power and storage into mere thin clients with everything from note-taking tool to entire operating systems offered as SaaS. This entire problem happened because the 'freedom' part of 'FOSS' got de-emphasized in-lieu of profiteering.