For the most part, the "they" you refer to is the community at large. By far the most flagging and down voting is community members, not the mods. And it's not "silencing topics worthy of discussion", its "avoiding topics that have empirically generated mostly uncivil, non-constructive flamewars". I've made comments expressing this distinction a number of times in response to comments such as yours (silencing/censoring worth discussion; why did this get flagged; this particular political view is always killed), and they've been consistently some of my most-up-voted comments. That indicates to me that this is an idea that has relatively strong support from the community as a whole.