It can be that people have downvoted it because they suspect roland indeed knows what the opinions of LW:ers [1] are and is trolling, but far more plausible is that most downvoters (of that comment) did vote just because it is a comment written by an unpopular author on an unpopulat topic.

I'm unconvinced either way. I suspect that some degree of unpopularity exists is relevant, but it also likely extends from issues such as those mentioned in my remark above. People have given Roland suggestions about what he needs to do to get people to actually listen and he hasn't done them, even when those suggestions (like the PredictionBook suggestion) would take minimal effort.

There's a certain point where on loses patience with actions like this and wonders if someone doesn't really want to convince everyone else but just wants to feel that that they have the secret knowledge and is smarter than everyone else who just won't listen.

[1] Is it possible in English to use the Nordic habit of separating abbreviations from suffixes by a colon? It looks useful, but I thought it is permitted only in Swedish and Finnish.

It isn't common in English. I've seen it occasionally, but generally from non-native speakers. I do however think that it is common enough that people will recognize what you are doing and it won't disrupt readability.