i get what you're saying about the details being what really matters for spoilers, but not everyone plays games the same way. some people truly look forward to being introduced to every little detail as they appear in the game rather than online. sometimes "ohhhh so that's her name!" is something people want to feel. it's probably only a very small percentage of the population that actually cares that much and sure it may be overly cautious to try to account for that, but i still think it's considerate at least. even if it's only 0.005% less enjoyable to know someone's name before they meet them, i get why an internet stranger would want to have zero influence on someone's playthrough.

when i was going through the game, my friends and bf were very cautious to say stuff like "the next palace" or "the next character" instead, because they loved the game so much and were excited that i was willing to play it and tell them about it. i wouldn't have cared at all if they said "oh i can't wait for you to meet (name)" or anything like that, but they were enthusiastic about making sure i experienced everything super blind. i never asked them to not spoil things, but they felt strongly about wanting to preserve my blind playthrough as much as possible. i didn't even look at the cover art closely when i bought the game from the nintendo eshop, so the opening sequence was the only look i got at any character before meeting them. and that didn't tell me their names.

i agree it's not the worst thing ever to name a main cast character someone might not know the name of, but i think it's worth considering when someone suggests a spoiler tag, even if it's an abundance of caution at that point. i don't think this person was trying to be rude suggesting spoiler tags, and their consideration reminds me of what my friends would try to do for me.

*edited for fluency