"Algebraic types, by themselves, don't do anything to make things "scary" or Turing-complete."

That's what "offer enough degrees-of-freedom to become scary" is getting at.

The types themselves are no more complicated than non-algebraic types in the end. However it so happens that for historical reasons they have appealed to certain personality types who proceed to build glorious castles on top of them, and indeed per the "degrees of freedom" point, multiple different overlapping-yet-often-conflicting castles. It is easy to mistake those castles as being "algebraic types", which is not helped by the name, rather than being simple things which can be explained to children and could easily be used in an introduction to programming curriculum rather than conventional types.

Conventional types are also not necessarily that complicated, or don't have to be. For instance, the complexity of C++'s towers of subclasses and templates should be accounted to C++ itself, rather than as a fundamental aspect of conventional type systems. There's things like Go that use a much simpler type system that is not generally amenable to such towers of complexity, which is a rephrasing of the most common complaints against it.