The article concedes that there is an actual base load that's real (so not a myth) but then talks about another sort of related thing and says that's dumb.
Okay, but that isn't really base load. That's the other thing. Base load is real. It's statistics.
Base load is real by statistics. However it is otherwise a useless concept. People talking about base load are universally wrong - wind and solar work just fine even if they can't provide the base load they are talking about: because we don't need base load in the way they think we do.
Base load was a useful concept in the 1960s when the cheapest power plants couldn't follow load and so you needed to find the right mix between base load and the more expensive generation. Now that the old power plants are not the cheapest we don't care about it even though it statistically still exists.
The article concedes that there is a minimum power consumption. Thinking that therefore defines your generation strategy (e.g. I will have plants that constantly generate that minimum amount and the rest I'll handle with separate peak plants) is a myth.