Because the topic of the discussion was that there was oversimplifying and mashing several cultural elements in Mythic Polynesia. Someone said it did'nt felt different to what was done in the FR, another example of superficial research.
The counter naturally would be that proper research was done into the FR to justify the mish-mash. Then we're told out of the blue about the genealogy of the author. The implication seems clear that ancestry replaces research. It is possible that the OP meant something else by mentionning the authors ancestors. But there is a strong chance it would be offensive, such as one's ancestry mattering on what one can or can't do. Could you in turn clarify how you understood "he's of european descent" as an answer to "this is a poorly researched hodgepodge of things relating to several cultures"
You are leaving out a key element of the argument, which I believe is coloring your sense for what the "counter naturally would be" because it is less "out of the blue" than you say here.
@Whizbang Dustyboots noted that Mythic Polynesia didn't have "actual Polynesian people involved in the project at all," wherein I think that we can also understand that there were not even people of Polynesian descent, such as people of Polynesian descent living in the U.S., Canada, or Sweden.* So we are not talking strictly in terms of superficial research, but also about the authors' own voice, life experiences, and background that they bring to the project.
As such, I think the implication of
@Incenjucar drawing attention to Ed Greenwood's descent was not that it confered any special expertise but, rather, that it reflects the author's voice: i.e., Ed Greenwood is a person of European descent living in a state founded by European colonists whose citizens are composed by a majority of self-reported European descent. And in American and Canadian schools, European history tends get emphasized as the hegemonic pre-colonial worldview, framework, and perspective for our history. We can talk about whether that "mish-mash" of European cultures in FR is appropriate, but
@Whizbang Dustyboots also said that it's good that writers and game designers in Europe are creating TTRPG that reflect their own idiomatic cultures.
* "The Design Mechanism was formed in 2010 by Lawrence Whitaker and Pete Nash.
A truly international company, The Design Mechanism spans Canada, northern Sweden and the USA."
Why mention Ed's being originally from Europe? So a black man in Brazil is ok to write about all of African culture? or an Asian born in the States gets a free pass on anything Asian?
Ed Greenwood is from Canada, but he is (presumably) of European descent. IMHO, it's not about giving anyone a free pass. It's about constructing an appropriate comparison. Mythic Polynesia didn't have anyone of Polynesian descent working on it, and it's the year 2022, a time when sensitivity readers are strongly recommended. Ed Greenwood is of European descent, and he developed the Forgotten Realms between the '60s and '80s before sensitivity readers were really a thing, first publishing it with TSR in 1987, roughly 35 years before Mythic Polynesia. FR obviously isn't getting a free pass, because Tomb of Annihilation got raked for Chult.
If people from these respective European nations sincerely care about what they may see as a negative depiction of their respective cultures in this FR mish-mash of European cultures - though I have my doubts how their good faith - then they are welcome to respectfully voice their concerns to WotC.
Do you genuinely care about the depiction of European cultures in Forgotten Realms,
@AnotherGuy? Do you want WotC to change Forgotten Realms so that it better represents the plethora of European cultures?