Not sure if I agree it's meaningless. In most cases it does mean what it implies, even if it doesn't have regulatory backing.

In the UK we've got all sorts of labels like 5 a day, the red tractor to imply it's of a certain standard and from a domestic farm or even the vegan label. They're all basically meaningless labels rather than something that's based on the actual product, but they still tend to track with what they're saying they are in most cases.

Don't take everything at face value, but also don't waste your time worrying that everyone is lying to you barefaced

I read the article and that’s not what it says. It’s actually about meat and dairy industries trying to stop plant-based products using terms like “mayo” or “burger”.

Plant-based means plant-based, as far as I can see.

“manufacturers should take care to clearly label their products as plant-based to the extent they are offered as an alternative to an historically animal-derived product.”

The Committee “encourage[d] FDA to provide clarity around labeling of plant-based foods that use traditional meat, dairy, and egg terminology especially as it relates to such product labels with clear and conspicuous descriptors such plant-based, veggie, vegetarian, or vegan.”

The content and restrictions of these laws vary widely. Some statutes permit “qualified labels” that either include “plant-based,” “vegan,” or other language indicating that the food is plant-based on the packaging “prominently” or “conspicuously.”

“It shall be unlawful for any person . . . to label, advertise, or otherwise represent any food produced or sold in this state as meat or any product from an animal unless each product is clearly labeled by displaying the following terms prominently and conspicuously on the front of the package . . . [for] plant based products as “vegetarian,” “veggie,” “vegan,” “plant based,” or other similar term indicating that the product is plant based and does not include the flesh, offal, or other by-product of any part of the carcass of a live animal that has been slaughtered.”

Whether or not it's a meaningless phrase, it seems in the article you provided they're still at least correlating the terms "plant-based" and "vegan", if not equating them.