the article is focused on ultralight/experimental aircraft engines. I use Pensoil in my experimental aircraft engine, a Rotax 503 DCDI, but I would not recommend that oil for karting. This is a larger, air cooled engine and max rpms are only about 6,500. Besides, it is a bit smokey. Just for reference though, I regularly run my cylinder head temps at 350 degrees, and reliability of my airplane engine is a Lot more important to me than a kart engine.
However, as the article states, a blend generally offers the best of both worlds. I know that Klotz offers a synthetic / castor blend and I am amazed that more people in karting don’t demand use of an 80/20 blend of synthetic / castor blend. The syn does a much better job of lubricating while the 20% castor both protects while the kart is sitting idle and it also has an extremely high flash point so it helps reduce damage during an overly lean run. The lower percentage of castor also reduces varnish.