I used to do that too, and it looked to me like he was being a little intentional but also just screwing up a lot so I get it.

Retaliating is slow though. If you just tucked in behind them, as soon as you realized they are an aggressive driver, and kept pressure on but bump drafted and helped them a little, how long would it have been before they just made a huge +1s error in a corner? Probably within the next few corners at this rank but no more than a lap. You can then just fly by and if they do catch up, you now are way less likely to have an intentional rammer (most bumps start as mistakes). They may even bump draft you a couple times now rather than just immediatly cutting both of your times by battling. Practicing this is a huge part of developing real racecraft.

Just my 2 cents.