I expect it is more a case of 100% concentration on getting their car around the track so no idea what is going on behind them. Trust me, this attitude has nothing to do with the car, it is just that those cars were fast enough for it to be a problem for you.
Even F1 drivers have the same problem. But the fact is, if you want clear laps you make them yourself if the other people are not coming to the party. Slow down on the back straight or somewhere that won't affect your laptime and make enough space so that you will not catch up with them. You had three flying laps to sort it out...
It is exactly the same problem you get on the Great Ocean Road etc...