If they admitted liability, people could sue for individual damages on top of the settlement. It's a buy-out, water under the bridge kinda thing, because individual lawsuits would cost years, would cost each individual thousands, and could cost 3M even more once all added up. It's a legal logistical nightmare.

Instead, people are offered a one time payment to basically drop the case. I think a lot are happy to take it because it means they don't have to fight a tedious legal battle.