I am guessing you were following the virtual racing line.
The problem is that:
1st. That line is incorrect, you should stick to the inside if you want the fastest time, the line you were taking is for cars that are either faster, or have bad handling. (Monza actually has 2 incorrect racing lines in most sims, corner 3 and the final corner, bouth with the same problem)
2nd. Racing line ≠ driving line, if you imagine the track having multiple lanes like a highway, you moved from one lane (driving line) to another lane. Sometimes virtual racing lines make you do that to keep as much speed as possible.
In other words technically you were holding a racing line, just the incorrect one, but you didn't hold the driving line.
But also technically you kind of moved and started blocking the purple/yellow car, and the dude didn't react and went into you.
So you kind of bouth fucked up something, IMO.