A contrarian may suggest that debating 3 on 1, in such an obvious display, and prevailing, makes the 1 look 3 times stronger, and the 3 look as weak as one third.

That's called winning in the eyes of the audience.

We like winners.

Also, there are not two parties. The GOP and Dems are one party.

The two parties we have are DC (and their propaganda machines - including debate moderators), and We The People.

It's US vs Them.

A contrarian may suggest that debating 3 on 1, in such an obvious display, and prevailing, makes the 1 look 3 times stronger, and the 3 look as weak as one third.

That's called winning in the eyes of the audience.

We like winners.