I think he's saying that his "professional journey building OSS" is over. ie his day job needs to generate income.
The abuse part exists in all software, free and commercial. But it's especially galling when you did the work for free. OSS also tends to attract, um, shall we say, those who are likely to be uncomplimentary. (Spending money on things means you're more likely to like it.)
The root point though is well made, and another annedotal data point - relying on random "companies supporting you with voluntary payments" is not a business model, and fundamentally misunderstands how businesses work.
Hint - If you don't -invoice- then youre not getting paid.