This applies equally to Free Software and proprietary software. "Don't like it? Don't use it." Your complaining isn't going to make the software better.
Decide on a course of action that will resolve your complaints, and then act on it. Posting to HN, "look at those l4m3rz at Firefox not implementing my features! They suck!" does not count because the logical conclusion of this action does not lead to increased happiness (either yours, or the wider community). It's like a little kid complaining to his teacher, "Johnnie hit me!", the teacher asking Johnnie "Why'd you hit Bobby?", and Bobby saying "Because Johnnie hit me first". The end result is a couple of sore schoolkids and an irked teacher. As adults, we need not let our actions devolve this way.
So, if this issue bothers you, you need to suck it up and stop using Firefox, or suck it up and implement the damn feature that you obviously care so deeply about. If you don't care about your feature enough to implement it, why should anyone else? Why are other people different from you? Because they've implemented features before? You expect free work from people that have given you a free product, simply because they have proven themselves willing to work for you for free before? Right, that make sense.
The advantage that free software projects have over "don't like it, don't use it" is that any user can change the software and other users will be thankful for the time and effort you put in. That's what being an adult is like.
Ultimately, all free software is based on altruism; people contribute because they want to. If you don't understand the concepts altruism or community and just want to take and complain, then you're not going to get any argument about how you should take ownership of issues that concern you.
There are many cases where this is not true. For example, any feature request based on a bug report. It's true that a bug report is in a different forum of complaint. But unless you can point out something that makes feedback from this forum useless and bug forums not useless, I'm pretty convinced this is generally false.
> So, if this issue bothers you, you need to suck it up and stop using Firefox
You can use this same argument to forbid criticism of anything. While I don't want to accuse you of doing this directly, it strikes me that if an argument can as easily be used for something obviously nonsensical as what you're actually using it for, it might not be a very good argument.
The point is simple: Firefox gives you everything you need to decide your own destiny. If you decide on a bad one, why should Firefox be blamed?
"Just pointing out flaws" is a good thing, too, but it would help to balance that with an equal amount of discussing his argument.
I think his argument is sound even though he doesn't have a pleasant way of arguing it. But similar to the point he is making about FOSS Projects - in that they do tell people "Either you're helping, or using, or you're not helpful", you are not helpful.
If you insist on being a "consumer" of a FOSS project, you insist on being something that they have no use for. That's your decision. You cannot argue that that is their problem.
And again: No, they are not immune to criticism, they have just set up a way in which criticism is handled in a particular manner, ie. channeled into discussions or in hands-on fixing. If you don't use either, you don't need to act surprised that they don't appreciate your criticism.
Is all feedback bad now because you have the opportunity (however unrealistic to many) to just sort it out yourself, or just use different software?
Or do you only dislike the concept of feedback when it's not positive?
This entire topic was about people kicking some dirt at Firefox because it didn't have individual line number markers until now. That's not feedback, that's not even just complaining anymore.
Of course feedback isn't bad and even complaints aren't bad - if they are directed at making the situation better. If it's just random people bitching in their own blog or a comment site like HN about how slow, bloated or whatever the criticism-du-jour-X of firefox is, that's their right, but it doesn't get anybody anywhere and they shouldn't pretend like it's Mozillas fault for not having a process for addressing and pleasing them.
If they want to actually see Firefox progress, they need to put their speech where it is heard and put their hands where they help. People who do neither are complaining for its own sake or to show off how much better alternative-option-du-jour-Y is, to them. Both don't get anybody anywhere, so THAT is bad - has always been, will always be, anywhere.
On the other hand, if you are looking at Firefox from the perspective of a consumer deciding between browsers, then the complaint is valid, assuming line numbers are important to you. They are kind of basic, and the product has gone long without having them.
> Ultimately, a free software project lacks feature X because you haven't added it yet.
This is also true of proprietary projects. I can edit the machine code or clone it. This fact doesn't invalidate observations of behind-the-times features in proprietary projects. In OSS, the barrier to entry is lower, but still substantial. Likewise, it's reasonable for us, as consumers, to observe when OSS projects don't implement things we want. I don't hold them to different standards merely because I have been invited to spend my valuable hours working on them.