I agree about the pulling over, but that's done less and less in the US, and I've seen signs about not driving on the side of the road. So there is a legal aspect to it.
I had never seen people do that until I moved to Texas over 20 years ago, and by that time it was only the old timers who did it. It's gone by the wayside, no pun intended. I think here people are also afraid to run over something and puncturing their tires.
Now in Mexico, the pulling over thing is not only a constant thing, but many people simply drive with their cars halfway across side line, so that only half of their car is in the actual road. I do it now down there as well, and just pull over to the left to pass, and move back over. In addition, if you're passing someone on the left, you leave your blinker on all while you're doing it, so the cars behind you know you are in passing mode, and will be moving back to the right momentarily.
Lastly, if you're going to make a left hand turn when you're on a well traveled highway, you pull All the way over to the right, onto the side of the road, with your left turn signal going, and you sit and watch for a break in the traffic both ways, then cross over. Doing as we do in the States, stopping in the middle of the road to turn left, even with your blinker going, is a sure fire way to get plowed into from behind.
Because of all the above, tailgating is basically non existent.
In my personal opinion, I think Americans are afflicted with a bad case of the "I'll show you's"
I'll show you for going slower than I want you to, and tail gate you.
I'll show you for tailgating me, and slow down, and not even think about if you have the opportunity to pass.
I'll show you for needing to pull in front of me so you can turn off the road
And so forth.
Our egos are so stupidly bound up in this driving experience, and having the control, when all we're really doing is going from point A to point B, and tailgating, speeding, passing or preventing someone from passing will not get us to point B any faster, or if it does, by literally only a minute or 2.
Then, when we get there, we'll sit in our cars checking our texts for the time we "saved"
In any event, it doesn't matter what the driver slowing down so the other can pass is feeling, it's all about How the person tailgating you is interpreting it.
They are already "showing you" to not drive slower than they want by being on your ass. I don't have to wonder much how they will interpret you slowing down.