Many of us have been using software from Mozilla, and Netscape before them, for decades now. Generally we've been happy with the software. We were more than happy with earlier versions of Firefox, in fact. But lately we've seen changes made that have not benefited the users of Mozilla's software.
Your comment actually describes some of the problems we're talking about. Users and developers now have to jump through one hoop after another just to get a basic installation of Firefox working.
It wasn't always like that. We used to be able to download a sub-10 MB installer, run it, and have a usable installation of Firefox ready for use.
Now we have to choose from the "correct" stream, download a 40 MB or larger installer, run it, change numerous about:config options to allow us to install our own custom unsigned extensions and to disable unwanted functionality that Mozilla has added, manually remove unwanted toolbar buttons, install a number of third-party extensions that also fix additional problems introduced by Mozilla, and in the end we're still stuck with a user interface and a user experience that isn't very good.
Now if we're developing extensions, we'll have to also jump through more hoops thanks to this signing process. You say it "takes only seconds", but I've seen enough comments here from other developers saying they've been waiting months for reviews. That's not acceptable.
Firefox used to get better with each release. A new release of Firefox was something we'd look forward to. But lately, each new release of Firefox has brought us new problems to deal with, without bringing any notable improvements.
Repeatedly disappointed people will express their disappointment. Don't misinterpret it as "hatred". See it for what it is: disappointment!