The point was that getting elected is not the most important thing other than for individual egos. What politicians who actually care about their ideology should be doing is looking to the best way for them to progress their agenda, to have influence over governance.
For example, Green Party under Caroline Lucas managed to progress the green agenda far more than one might expect from their electoral success. She made focused coherent arguments (and still does).
Polanski should realise he's never going to become PM, he's never going to have a majority in Parliament (I would question if there's even a safe-enough constituency for him to get elected as an MP). So if he believe's his ideology (rather than wanting Social Media and press attention) then it becomes how to move towards his ideology. Coming out with extreme economic proposals it just going to get his ideas dismissed and ensure Green candidates don't get elected.