Forget the wording 'centrist', parent is trying to describe the need for a party that seeks allies from all angles rather than trying to produce outrage towards specific groups of people in a lazy effort to foment in-party support and credit.
In recent years, I guess due to success of certain parties, everyone has decided that it is in fashion to have a group to demonize - to hate. This (necessarily) creates a group of disenfranchised people that have an axe to grind.
It used to be that political parties demonized far entities that were as far outside the voting American public as was feasible; now it's fashionable to attack people that constitute American voters. Now we have hordes of people that were demonized by one side or the other, and a lot of them want to vote one way or the other out of pure spite rather than political interest.