Usually it's because of an initiative by the Long Now Foundation that is supposed, among other things, to raise awareness about their 10,000 years clock and what it stands for.

See https://longnow.org/ideas/long-now-years-five-digit-dates-an...

And I, semi seriously, say that it's only the "Medium Now", because they only prepend one zero.

But I hate it. It makes most readers stumble over the dates, and it does so to grind an axe that is completely unrelated to the topic at hand.

Everyone hates it.

There are always a few trolls who complain about how other people spell their words, wear their hair, format their dates, choose their clothes, etc. Usually on HN these complaints get flagged into oblivion pretty quickly. But most people don't care, preferring to read about things like the interaction between technological development and digital art forms than complaints about whether "aluminum" should actually be spelled "alumium".

I would rather attribute the term "few trolls", if to use it at all, to the people pushing an agenda for a thing happening in 8000 years.