The key sentence in the post you linked which constituted more than 50% of the words being stated by the poster and yet you somehow conveniently missed which completely negates the whole narrative that you're trying to promote:
Speaking as an open source maintainer, if a tech company would like to pay me to do ~anything for my open source project, we can sit down and talk about my rates.
Which means this person is NOT simply a volunteer as you insinuated here:
When someone suggested a level of effort to be put on code checked in to prevent security issues from happening, the maintainer pushed back, stating that they will decide what level of effort they'll put in, because they're doing the work on a volunteer basis.
but in fact is available to be paid a fair rate for the labor they perform. In fact your entire description of the post is mischaracterizing what is being said in the post.
I don't know how you could have accidentally missed or misinterpreted one of the two sentences being said by the poster, and the longer of the two sentences at that. It was also the first sentence in the poster's statement. It seems more likely to me that you missed that on purpose rather than by accident. Maybe you're just so eager to find evidence to match your narrative that your brain registered the entire point of the post incorrectly. Allow me to reframe what's being said to simplify the matter:
As a self-employed contractor, if you demand that I perform free labor for you, I will decline that request.
Now just add a much more frustrated tone to the above and you get the post you linked.