Abstaining from voting while minting might be available for Nu in the future.
For Blocks & Chains Exchange it seems to be on the agenda.
At the moment a vote for a grant or hash or whatever is counted as “for the cause”, not finding a vote in a block is counted as “against the cause”.
If you don’t configure votes, you vote against all grants, motions, etc.
Delegating votes to specific people is available through data feeds.
Delegating votes to “the mainstream” would be possible with frequency voting, which unfortunately isn’t on the agenda.