This will long be forgotten by the end of March, when the primary rolls around.
Since it is an open* primary, Bishop's only hope is for progressives, and others, unhappy with Brown, and who would never vote Curry, is to vote for Bishop, instead of "making a statement by not voting". Not voting is a sure way to get stuck with someone you don't want as the winner. Since qualifying is over, it is probably too late for Bishop to renounce the GOP and become an independent, since an "R" behind his name will scare away some Dems, regardless of his positions.
* "open" may not be right word (non-partisan?), but the point is, everyone votes for the same slate of candidates, without regard for party affiliation, or non-affiliation.