Earlier quoted context omitted.
It was much more likely meant to mock the Christian tradition of eating fish (actually the point is, not eating meat, but then people naturally turned to fish) on Fridays (and for the hardcore ones also on Wednesdays). This same Christian tradition has become a bit of a joke nowadays since fish is now more of a luxury and is more expensive and less accessible than meat, which is now super common and much cheaper.
What you're describing is the modern post-vatican II Catholic fasting tradition. If one follows specifically the Russian Orthodox fasting rules strictly, you'd be approximately vegan for half of the year (every wednesday and friday, as well as lent, apostle's fast, dormition fast, nativity fast, a few others sprinkled in, etc). On a conventional strict fast day (other than e.g. Clean Monday in lent where you eat noth…
> Another opinion holds that Thursday was chosen as a poke in the eye to Orthodox believers, since their fasting days are traditionally Wednesday and Friday (official doctrine did all it could to encourage atheism).