It’s a massive non-issue. If Trump said he was part Native American I probably wouldn’t care either. I think most would assume he made it up because he has a history of making things up. Warren does not. It’s odd to assume that she personally made it up when stories like this are incredibly common, especially in places like Massachusetts (that of parents telling their kids they’re part Native and so forth), partly because they’re not hard to believe.
If Warren was still going around playing up her “heritage,” I think it’d be a different story. But the only people talking about it are Republicans, obviously just in an effort to bring her down and/or make fun of her (Trump’s “Pocahontas” remarks).
She has no obligation whatsoever to take a DNA test. Why should she? That can’t end well. All my life my dad’s told me he’s half French (therefore I a quarter). A few months ago he took a DNA test. Turns out he’s not French at all.