It is stupid to shout "get out of my way", but blue flag drivers should have some common sense too.
Fact is, if a driver is lapped, then he is going MUCH slower than the guy behind - doesn't matter if he joined mid-race. Moreover, when drivers have to pit in race things become even worse. Example scenario(based on real "story"): I am fighting for 1st place, the other driver pitted already.. I'm trying to get some time so I can exit pits later in 1st place, but I am stuck behind blue flag driver that is going ultimately slow. The track is fe club and we are after T1 - the chicane - he is super slow yet I'm so close that I have to slow down to not crash him.. I try to pass on the outside on uphill leading to next corner, but i get blocked to right and pushed to the grass.
That is the main problem, when blue flag drivers block and fight as if they had a chance to overtake the driver that is lapping them. I can live with those who not let pass clearly, but those who literally block even if their driving is very slow? Ehh.. Well anyway, the scenario I wrote - I finished the race 2nd, because I lost a lot of time behind that blue flagged driver.
What I do when I get blue flagged? I check my mirror and map to see how close the driver behind is, when he gets close I leave him space to pass in first safe place on the track. Why? Because I know I'm much slower when I'm being blue flagged, and that by blocking that driver, I can only ruin his race and make him enjoy live for speed less.
Cheers, Kamkor