>>213425087
>Is there a Japanese equivalent of the term "moralfag"?

I don't know if the original questioner will read this very late reply, but I will write my opinion anyway.
As he said >>213427323, I also doubt Japanese has any expression that corresponds perfectly to it.
Similar expressions that occurred to me include:
>自治厨(autonomy fag)
This is a derogatory term referring to people who point out violations of rules in forums, threads, etc., even though they may be very minor and harmless ones.
This suffix "厨(ちゅう)" would be one of the oldest Japanese internet slang that is attached to a noun for an action to mock the person who does that. It is derived from
>厨房(ちゅうぼう, kitchen),
which has the same pronunciation with
>中坊(ちゅうぼう),
an abbreviation of
>中学生の坊や,
that is, immature and incompetent people.
For example, 指示厨(しじちゅう) means people who make commanding comments about playing style during a live stream of video games or so, often confusing or upsetting the streamer and ruins the stream.

>正義マン
Literally "justice man".
This is an online term that sarcastically refers to people who express moral opinions or behave in a morally good manner.
This is a derogatory term by people who feel uncomfortable with such opinions or behaviors, so those who are called this are not necessarily overly moral.