It depends on the context and environment where these topics come up. A 36-page thread about flavored crisps, especially in a casual setting like an online forum or social media, is fairly plausible because people love talking about food, and these kinds of light-hearted debates can spiral into long, humorous discussions.
On the other hand, a random unprovoked mention of Eurocommunism is probably less likely to arise in everyday conversation, unless you're in an academic or politically engaged group. Eurocommunism, a specific leftist ideology from the mid-20th century, requires some knowledge of political history, making it a more niche topic compared to flavored crisps, which appeal to almost anyone with an appetite!
In short: the crisps thread is much more likely in most casual human contexts, unless you're hanging around political theory enthusiasts.