I think it's more aimed towards his tendency to go against the (left) mainstream of his day and start fights - he argued for a delayed or stopped reunification of West and East Germany, he often criticized people for not dealing with their Nazi past thoroughly enough (which bit him when he disclosed his own previously secret Nazi past just a few years ago), he always worked in politics (mostly supporting the SPD).
"Wenn es dann kracht,"
you can also translate as
"where there's a fight"
so there's a bit of a double-meaning here - "krachen" means that there's noise from his crushing nuts, but it can also mean that there's a conflict [1]
I tried to convey this with gnashing, which is also something that literally happens when you chew nuts as well as idiomatically when you fight, when you gnash your teeth out of anger.
"Wenn es dann kracht,"
you can also translate as
"where there's a fight"
so there's a bit of a double-meaning here - "krachen" means that there's noise from his crushing nuts, but it can also mean that there's a conflict [1]
[1] http://www.duden.de/rechtschreibung/krachen "(umgangssprachlich für streiten)"