

Everybody learns the Latin alphabet and English in school (used to be Jr high but pushed back to elementary recently). Proficiency levels are low, especially in speaking and listening, and shyness/fear of mistakes are factors. However, reading can be pretty decent. Of course, people very good at English also exist.
Could also be that many use machine translation, at least for the output side.
I don’t think most people would care unless the community rules forbid it. Some might be curious, some might skip it, and you might get a nettouyo being a racist twat every now and again.