At the time “man” was often used to reference the human species as a whole. Like, when they’d say something like “the dawn of man” they were specifically referring to the earliest humans regardless of gender.
Obviously this is not particularly representative of roughly half the species, which is probably why it’s less common today. Taking that into consideration, though, TNG’s intro is arguably more colonialist than TOS.
TBF in the ToS it was ”Where no man has gone before”, not “Where no one has gone before.”
So if it was aliens then the statement was correct, we’d just have to skip all the weird human populated worlds they found.
“Man” and “woman” has never referred to humans exclusively in Star Trek, though.
“Mr. Data, you are a clever man - in any time period.”
And, not take any women along, which of course was never an option on Kirk’s ship.
At the time “man” was often used to reference the human species as a whole. Like, when they’d say something like “the dawn of man” they were specifically referring to the earliest humans regardless of gender.
Obviously this is not particularly representative of roughly half the species, which is probably why it’s less common today. Taking that into consideration, though, TNG’s intro is arguably more colonialist than TOS.
for most of the history of the word, “man” has generally meant all humanity, or any human.
male men were called something like “wer”, which survives in “werewolf”.