The old man was not trying to call you an asshole, just trying to get you to stop and think about whether or not you really want to be riding like you were. Considering his son died doing the same thing, he was probably thinking he was doing you a favor, like he wished someone had done for his son.

We all ride, so we all know how easy it is to let adrenaline take over. Sometimes all you need is a second to realize what you are doing is probably not worth it and should be saved for a safer area.

Unfortunately, you showed him that you don't give a fuck about him, his son, or anyone but yourself. I'm not saying you are necessarily wrong for pulling the front wheel up every now and then or speeding, but to do it in front of him right after he told you how his son died once again just proves that sterio-types exist for a reason - young does translate into stupid and inconciderate - at least in your case. Congratulations!