Please do not post such long messages, my bandwidth is limited to 110 Baud. Also, it not only takes a long time to download your message, but it takes several pages of paper to print it on my teleprinter terminal. Also, could you use EBCDIC? It takes alot of processing power to convert your very long message from ASCII to EBDCDIC.
But seriously...
Just imagine another organisation, say the EU, making an influential survey on an important political matter, requiring a certain OS, browser, document format or whatever that "98% of computer users use or have ready access to". What an outcry this would be here!
That is how it actually is and should be, the real problem is requiring people to install non-free software to be able to contribute to these things. With free software you can study how the process works, and even adapt it for your own needs, something that is simply impossible with non-free software. The remaining 2% actually have the freedom to take the supported tools and make them work in the manner they would like to, if the tools one needs are free software. So if you really dislike how things work, say that they are not supported in your browser of choice, you can study Firefox (for example) how it solves the problem and just copy the relevant code with maybe some modifications.
The problem you noted with browser independency was not really browser independance, but independance from non-free browsers which added various incompatible features that other browsers did not understand. This is no longer a very big problems, since at the time we did not have a free graphical browser, now we do.
The supported browser that the GPLv3 commenting process supports is a browser we all can install, since it is free software, so there is absolutley no reason not to require it. It is much like it isn't wrong to require GCC specific features in a program, or a specific free file format like OGG Theora for videos.
And anyway, if you don't want to use Firefox, you can always comment through email.