In the comments, it looks like Criggie gives you a very helpful rundown of the Physics of why that causes more wear. Sheldon Brown is a great resource for a lot of things, but in the long run, he was just one mechanic, sharing info with the world, and didn't get to put everything there or be completely comprehensive. I can tell you from my experience as a mechanic, you want enough b-tension to keep your pulleys off your cogs, and that's about it, too much more, and as Criggie said in that other post, your chain will have less contact with your smaller cogs, and will wear them faster.
As for a citable source, PDF of Shimano general instructions Page 20 tells you how to set proper B-limit screw tension for several systems, even though it doesn't give a specific reason for why it's like that.