Opening on a philosophical note, the use of the term agitprop is absolutely inapplicable. Agitprop refers to government propaganda cloaked in popular entertainment. For the term agitprop to apply, there would have to be a government body of doctrines that were promoted through drama, literature, and music. Whatever the flaws of this site, it is not the mouthpiece of a socialist regime hellbent on inculcating a willingness to submit to tyranny and absolutist thinking.
From time to time, emotionally inspired philosophical conflicts of worldview, like those often branded with the term culture wars, emerge in questions. Questions about Zionism, intelligent design, and sexuality are the typical topics, with vocal parties from religiously fundamental and secular and atheistic voices often falling at odds over topics like political philosophy, evolutionary theory, and homosexuality. Sometimes heated comments are exchanged.
The site's moderators gravitate towards mildly restricted speech typical of the social democracies of Europe more than the more permissive Anglo-American nations who tend to allow hate speech, religious fundamentalism, and pseudoscience equal voice. All three moderators consistently allow the community to sort out such conflicts for itself. This is why the site has a vibrant collection of contributors who often disagree, not only in what constitutes an appropriate question, but what constitutes an appropriate answer.
Since PhilSE is an international community, there is a range of what is "acceptable" and it would be difficult to impose acceptable on these edge cases top down. In Germany, Nazism gets you arrested. In Illinois, it gets you free representation from the ACLU and a parody in a comedy like the Blues Brothers. The moderators are volunteers from three separate European countries, and even the cultures of those nations differ in subtle ways.
Lastly, there is always a way of specifying your reason for closure. Why add a bunch of mechanisms when the mechanism in place already allows you to explain why you vote for closure? To quote a wise man, if it ain't broke, don't fix it.