It's virtue signaling. Choosing the soy "milk" at the coffee shop, loudly, demonstrates to the other patrons that you're "woke" and "care about the environment". Never mind that if you actually cared about "sustainability", you wouldn't be living in a state that imports vast amounts of food, water, and energy from hundreds of miles away in the first place.
It's basically a religion at this stage, and virtue signaling lets you pay your penance in advance. One refusal of a disposable straw compensates for one six month backpacking trip in Nepal, or one vacation in Aruba, or something like that.
And this will get modded down into a smoking crater, because people always get angry when you make fun of their religion.