That page is commercial spam (or "veiled spam"). It serves no other purpose than to get a link to his own product site, no discussion, no nothing. Just: For the special price of 999 Euro you can get your own. How is that quality content?
It is also spammy in that it doesn't nofollow external links on comments. Those links should have been nofollowed like 6 years ago. That they still aren't, is telling about MetaFilter's knowledge on SEO. You know that Google sees your site linking to bad sites, and what do you do? Complain about it? Fire people due to an update 2 years ago? Or do you simply take action to fix it?
MetaFilter doesn't have to be (and isn't) excluded from the internet. It just doesn't have to rank well for terms like "Gomboc".
It became alright to derank "inane babble" the moment it increased the satisfaction of search engine users. Which is pretty much from the beginning of search engines. It is user metrics that count. Statistics don't lie.
It does not matter that you are uncomfortable with an algorithm. I think I don't get your "judged as an attack"-part. The alternative is not using a search engine that relies on algorithms.
I did a casual investigation of MetaFilter. It has not changed much over the years. The pages I did look at were all of the level of "inane babble". One line comments. Puns. Not adding much to an already thin topic. Perfectly alright to have a place on the internet to debate how to get your friend to take Viagra. But not much need to rank that for men's health topics, relationship advice or even Viagra.
http://ask.metafilter.com/57406/Bright-light-flashes-in-my-r...
Now would you want to find that page when you are searching for those symptoms? Or would you want credible medical advice?
If it is moving the goalposts, it is moving the goalposts to better quality content. Those visitors not going to MetaFilter are not gone, they are catered to by other sites. Every tag on MetaFilter has a specialist site now. Ranking MetaFilter so high before 2012 was a present. MetaFilter doesn't deserve to be deranked any further, but it doesn't deserve huge pre-2012 rankings either. In my experience, todays SERPS are much better than ever before, and the complaints are biased, reminiscing good old times or influenced by the fact that some paid to post on that site (You'll defend it, as you don't want to back a losing horse, and your experiences with the site are probably good).