Now imagine adding an explanation of american football rules on every article about it, of which there are probably hundreds written a day.

I have no clue about american football rules - I barely know the sport exists, the ball has a funny shape, and that it's popular in the states. Still it would be absolute nonsense to explain their basics every time someone talks about them and I won't expect anyone to do so. Explanations like that will just annoy the vast majority of readers, who will have a preexisting interest in the sport and thus will already be familiar with the rules.

That said, I had even less of a clue what the hell conkers is. Luckily I have basic technological literacy and was able to find the wikipedia article[1] in a fraction of the time it takes one to complain.

[1] https://en.wikipedia.org/wiki/Conkers

No one said it was true for every game. Conker is more akin to corn hole than football, but maybe even more obscure.

It's not obscure in the UK. You can find any number of equally 'obscure' cultural practices referenced in American newspapers without explanation. It's unreasonable to expect a British newspaper to be free of British cultural background assumptions just because it's viewable by an international audience.

It appears that about 38% of visits to their site come from the UK, so it might be that the majority of their readers aren't familiar with conker. https://www.similarweb.com/website/theguardian.com/#geograph...

I guess your point makes sense, though. There isn't the obligation to explain anything. I just personally think it's good writing to anticipate what your readers may not likely understand.

The NYT has 150 million monthly readers globally of which 27% are international. I still wouldn't expect it to insert helpful explainers every time it mentions a cultural phenomenon specific to the US.

It's the guardian. You're not the target audience. Not everything is about america.

To be fair it was written in English.