Well, it’s a neopronoun, so while it’s popular enough for most people to understand what it means, in my experience “iel” sadly gets a lot of pushback (“oh but we don’t do that in French” etc.) which means it’s rarely used in contexts other than to refer to non-binary people who have expressed a preference for “iel”.
Maybe it’s just a popular opinion on here, so when people click on the thread and see their opinions being mentioned they don’t add more comments saying the same stuff as there’s no point.
But then when they see someone else say something that differs from their own opinions, it’s not unlikely that people tend to reply more to try and express themselves if they feel their opinions are no longer in the majority.