The effect here is more about people claiming lateral authority, rather than the base claim of authority in the first point. But I take your point.

I’m also underqualified for my position and am wary of credentialism. But if I’m looking at a topic I don’t know well — e.g. seismic building codes- I have to start somewhere.

Software engineering is thankfully a field that is particularly accessible to people without formal training. Demand is high, functional skills can be proven on the spot, and employers are (usually) not in a position where their hiring decisions have potential legal consequences.