I checked the replay Mika provided, and I cannot see anything wrong on what Vyacheslav did. Mika, you've been unlucky to catch him in a series of chicanes, so you lost a lot of time there. People cannot disappear from the track. I agree that back markers should try their best give road, but always in a predictable way. As you can see he even tried to move away after the 2 chicanes, and there you were almost colliding because you didn't expected that.
It isn't easy for them too. Especially for new drivers, with less experience, isn't easy at all. I'm sure they try their best not to ruin the leaders' race. I've been through that many times. It's something that puts you in a lot of pressure, believe me. you need to check the road trying not do mistakes, check the mirrors, and try to find a spot in which you can give road easily without interfere. And you know you've to do it as fast as possible. Believe me, isn't easy.
I can understand that you were fighting for the championship and every seconds counts, but back markers are on track with you guys. Just as we saw many times in TV, even F1 drives can gain or loose a lot of time trying to overtake them. You've to be lucky. Sometimes you get them in the straight an you can gain using their slip stream, other times you get them in the worst possible place of the track in which there is no way of overtaking unless forcing it.
It's always a gamble, but it's part of the game.
Don't forget that you guys are even 5 seconds faster than the guys on the back of the grid.
Just because we are all quoting something, I'll do it too. This is the explanation of the blue flag in iRacing:
Indicates faster cars are approaching. This flag is informational only. In all cases, it is the responsibility of the faster car to safely overtake the slower car. It is the responsibility of the slower car to maintain a consistent line. It is strongly recommended that a slower car being lapped makes every reasonable effort to facilitate a safe pass.
I've to be honest. I don't like at all that in iRacing, in fact our rules are different, but, from the other side, I agree with the fact that it's a shared responsibility.
Usually it's easier for the fast car to show on which side he wants to pass. As you saw exactly in this case, when the cars are close and is the slow car to make the move, it can even be dangerous.
My approach is usually:
1) if I see the fast car coming, and if it's far enough, I try to go off line to indicate that he can pass safely.
2) if I haven't seen the fast car in my mirrors soon enough, and I'm in a place in which is hard to overtake, I try hold my line and give road as soon as I can, but waiting the car back to make the move. I always try to be predictable.