In fairness though, it is easy for you to say that as you haven't spent years getting to a senior level. I'd guess the link that Kes posted was a Conference South game so a L2B referee, or possibly L3 if it was before the split of L2 came in. It is extremely difficult to get to 2B or even 3, one bad observation and all that hard work risks being wasted and you go back down. You can't control certain things like missing a bad tackle or a DOGSO, but this is controllable and the player really didn't need to do what he did as there were stewards on the pitch. This was a semi-pro and former pro centre half, pretty sure he could have just held onto the idiot until the stewards got there. I've stood next to Ashley Vickers, he is a man mountain and he just didn't need to react as he did.
If that was me I would be looking firstly at is it being filmed. As it was, and officially rather than someone with a phone, I'd be asking myself what would happen if the FA got that video and I didn't send off. An incident like that is always going to go viral, so highly likely it would be a charge of failing to proficiently apply the laws, and at least a three week suspension, so yes I would have done what the referee did.
With no filming my immediate thought would be who the observer is. There are some that would take real pleasure in tearing you apart for not sending off, equally there are some that would back you for a common sense approach. You always need to know who your observer is, and this is an example of where that would be more important than ever.