I would think a lot of mods, who are either Highly Online Americans or their weirdo equivalents in other countries, are well aware of the UK usage, but simply e

I would think a lot of mods, who are either Highly Online Americans or their weirdo equivalents in other countries, are well aware of the UK usage, but simply expect Brits to give it up in order to avoid offending Americans and the global Reddit community that largely takes American-style sensitivity as its orthodoxy. And considering that Reddit corporate feels that anything that could stir up such outrage is bad for business, mods of popular subreddits may well feel pressured to come down hard on these matters.