Ok. This is actually not a but. It looks like VisualARQ is supposed to work like this way.
Yes, it should be always thinner. Is there any case where you think you would need projected lines to be thicker than sectiones lines?
Yes. There is, definitely. For instance, thickness of gypsum board is just 9.5~12.5 mm. In many cases, they are placed with double layers as finish materials. So, you need to use very thin line width for them in section. Otherwise, the wall outlines are represented too much thick. However, projection lines of the walls for which double layer of gypsum board are used need to be think to some degree so that it can be read more clearly than furniture or fixture. This is about hierarchy among elements represented in drawings.