You are of course right in the context of good riding, which is to hold one's line.
But I guess this question of 'how can I ride safely around unpredictable and aggressive riders?' is all in the theoretical, and doesn't have one answer. Someone clips your front wheel and you think 'I would have liked to get myself out of the way if that douchebag doesn't give people space' or if you create a small bit of space on your right and then get cut up the inside you think 'I should have held my line. What kind of douchebag undertakes?' So I'll walk that back a little and agree: holding one's line is generally the best course of action. But also giving myself a bit of space has saved my front wheel a few times in RP, eg when Billy Big Balls overtakes on the rise to the zoo then fades and drifts in too early. And also as recently as a week ago when I was out in the lanes, I was glad I didn't hold my line then. It's all split second stuff and the best one can do is ride reasonably and hope others behind follow suit.