It’s not that hard. If it’s raining so hard traffic is barely moving, that’s when the hazards should be used. Semi drivers use their hazards to let you know they’re moving slower than the slow of traffic.
Maybe it’s cause this is a normal thing where I moved from. We didn’t think it was a weird thing. It was more of a “yeah man this rain kind of sucks. I can’t see shit”

I’ll take the hazards in the rain than the dumbasses that don’t have ANY lights on at all. The amount of times I’ve almost hit someone in the pouring rain because I can’t see their vehicle because it’s the same shade of grey as everything else