It's not his decision and in the same time he's doing his job. Believe me that he also prefers to run WRC2 but Škoda wants him to take the Czech title.
Also I don't think that he's killing the championship. You can see that there is absolutely no decline of quality or quantity of drivers and cars in the championship. It's been exactly opposite in the recent years. Also the number of spectators is growing and speaking for myself I want to see him driving because You know what? He is the benchmark. You can see a lot of mistakes of others when comparing to him on same places.
There were 18 R5, 3 WRC and 1 S2000 on the first event and there will be likely even more in next rounds with extra bonus in Lukyanuk joining the show. You can take it as You will but I'm pretty happy about what we have here now regardless the fact that the master is winning everything.
By the way in Your opinion when Andreucci is winning championship after championship is he killing Italian rally?