I'm not sure where you live but what those cars are doing is the correct thing, in regards to laws and driving best practices in what I think are many places in the US. You shouldn't really be going left to get rid of them, even if that's legal where you are (it's not legal to go into the left lane except to pass in multiple states), or you are driving on a highway with three lanes in each direction. The cars should not really be speeding past you on the right either, but if you are weirdly switching lanes they might not have a choice.
Edit: actually, if they are tailgating you too close you might want to try to get rid of them, but tapping your brakes (to flash your rear red lights), or putting your hazard lights on briefly to get them to go around is probably better than going left one lane.