Comment by esperent

From my experience creating loaders for 3D formats (FBX, glTF, LWO) it's not loading the file that takes a long time, it's parsing the data in the file and converting it to a suitable format for rendering in OpenGL. In practice, most people use the terms "parsing" and "loading" interchangeably, or "loading" means "reading + parsing file".

There can be a lot of processing involved (looking at you FBX) or less (glTF, probably STL) but there's still going to be at least decompressing the binary data and copying it into buffers then uploading those to the GPU. So, without knowing how STL binary is specified, parsing 97mb in 165ms seems reasonable.