This might be the intended behavior, but it seems odd.

When the “removeLayerBelowMinVertexCount” option is disabled, i.e., set to false, on a polygon with holes, you are unable to remove the holes in the polygon by right-clicking the vertices of the holes in edit mode.

Despite preventing the removal of the layer (i.e., the polygon itself), one would likely still expect to be able to remove parts of the layer (i.e., the holes themselves).

https://jsfiddle.net/kas04bf3/7/