If that is trolling then... actually just revisit your definition. You say you asked a serious question and maybe you did at first, however upon getting a serious answer your responses could be forgiven for appearing to be silly in the eyes of others, I would have gone with misinformed but to each their own. Either way if the OP starts the silliness then others are typically allowed to then join in.
I suppose cookies are not a fundamental portion of site operations (maybe login creds, maybe preferences (some are account/server side) and probably some cover your arse in case the wiki or a subdomain or advert network or something in the future tries to set cookies. Thusly a cookieless version of the site might be possible, however as in the end it is mainly just forums for fairly light conversation for the most part (so not a bank, not a dating platform or similar, no a thing with terribly sensitive info as the main point) it was probably deemed enough that people who care would not make up enough of the visitor base to bother. To that end the token effort was done to comply with EU cookie directive ( https://ico.org.uk/for-organisations/guide-to-pecr/cookies-and-similar-technologies/
) and accept, live with the banner or leave the site was deemed a suitable selection of options, and leave is always an option -- it is the same line of logic that says if there is nothing on TV then turn it off.