The latter. (And at the party member level, the hostility might be greater in the LP than the governing parties - the SPD and Green party leaders are on the other side from the LP within their own parties.)

As for the non-PR element, 2002 was an exception when it didn't play that much of the role - with the SPD's sweep in the East balancing the CDU/CSU's sweeps in the South. You probably recall Unionist complaints on election night that the non-PR aspect stole them the victory as largest party, complaints that proved premature with an end result showing SPD just slightly ahead on list votes. (The SPD's advantage was just 3 seats.)

This year however, (I think jandsm gave us a link I regrettably lost) projections show no SPD direct mandate sweep anywhere, but a CDU one all across the South and central West.

_{*Lunatic*, n.
One whose delusions are out of fashion.}