Why I need stand behind the car with foglamps on? I don't always tailgate people car so never facing irritating. 
2nd, did you read my statement previously? I never say will simply open foglamps. I open when I feel behind the car too closed could cause of dangerous when emergency braking.
While you talking fogging or rain that's depending. We can on double signal or full lamp.
Conclusion, I switch On if behind car highspeed chase and tailgate, or reverse gear when area dark without good visibility.

There are always 2 sides of story.

Why people tailgate you?

First side of the story:
1. Some one driving recklessly regardless they are in fast lane / middle lane and simply flash high beam / tailgate etc.
2. Some one still tailgate you even though you already in middle / left lane.

This type of drivers are simply axxhole, just avoid to mess with them. Is not about fight with them, is about your own safety on the road.
Second side of the story:
1. You are driving slow in fast lane.
2. Driver behind already turned on right signal / high beam / horn telling you they want to pass, but you still ignore them and continue to drive in fast lane.

If you met either scenario above, you should feel sorry to the others & should not do that anymore instead of switch on rear fog lamp to irritate them.

Example: Driving 70kmh in the fast lane on highway. I will be like: What the hell are you doing there? Please drive in middle lane or left lane.
I'm real frustrated to all those bastard blocking the fast lane. Please be considerate to the others. Thank you very much.