I couldn't disagree with this more. The date doesn't just "often" provide important context, it always provides crucial context.

If the post truly has lasting value, putting a date on it isn't gonna change that. Pretending that leaving the date off gives it more lasting value just means you don't have confidence in what you wrote.

Leaving the date off a post so it "gets more shares" is just a scumbag move. End of story.