I think that bit, in bold, relates to the fog lights, not dipped lights.Hmmm. Not a very good piece of advice, IMHO. Who has been dazzled in daylight by car headlamps on dipped?
If it's raining significantly then how is there a problem with cars on dipped headlights ( and thus rear lights on )?
Someone's glance would see you. Without them , they might miss seeing you.
Where's the downside to it? Sweden doesn't think there is.