Question consists of two parts:

1) Why not lifetime? Because the rule said buy/sell.
2) Why does the rule state buy/sell? It was taken to the extreme to be useful in upcoming events.

BenchZowners question did not raise a valid point. He asked why AndreYang wasn't banned for life and he asked it because he forgot to read the rule. The discussion whether it does or does not matter if there's a financial transaction is certainly interesting and, as I already indicated in another thread on hwbot, it's likely that we need to update the rule.