Even if they're not the 1st, they'll just add more qualifiers: not the 1st woman? 1st woman in Marvel. Not the 1st in Marvel? 1st woman in the Marvel MCU? Not the 1st in the MCU? 1st woman in the Marvel in the MCU with a crew cut, 6 fingers, a build back better tattoo, marmalade gender, 12-time abortionist, lesbian on crack, and so on and so forth.

Besides, they aren't writing these articles for the nerds/fans that enjoy this content in the hopes that they forgot since the last time(probably less than 1 year ago). They write these for other people who don't care and have never heard of any other cape shit. A significant portion of their audience might be too young and ignorant to know about anything older than 5-10 years old.

Final point: they are prolific liars, so at what point do you expect them to be consistent or care about reality when they can state blatant falsehoods with 0 repercussions. Even if they get caught out, they probably turn off comments or block any dissenters in their bubbles so nobody else can pop their delusion.