What, no debate?
Years ago, there was a skit on a late-night show that featured a pair of comedians on a news broadcast. (Comedians playing comedians. Heh. I think one of them also played characters with monkeys, mangoes, and head bops.) After an introduction in which they mentioned one of the pair was on another continent with a time delay on the broadcast, the pair started to perform what was billed as their signature bit. If I'm right, the point of the skit was to illustrate the difference between the live and the onscreen performance of the same bit, the latter being about as funny as this brief analysis of the entire skit.
I brought up that long-ago attempt at comedy because of a discussion I heard regarding presidential debates. Under discussion was the possibility of using the current pandemic and any related quarantine periods as an excuse to keep one candidate from attending. Considering the options now available for long-distance communication, neither should be an obstacle to live debates, especially on the same continent (though video chats still go on the fritz every now and again). And couldn't office pods be adapted to have the debaters meet in the same location while maintaining quarantine?
Here's something else that sounds like an excuse - refusing to debate because to do so, to "dignify that conversation," would be somehow beneath the challenger's level. Maybe this woman hopes that the news cycle has forgotten how the challenger has already been defeated in debates within his own party, and his party knows it. Also, since coverage of this candidate comes from those whose limited self-awareness can't stand reminders of their flawed coverage (this refers to this - try starting at about 13:40 for some context, but the real display of those limitations starts at about 15:50), there might be something to consider in reports that voters' views might differ from what the polls reflect.
The challenger's party has looked at their candidate's performance and flinched. If this is the best they have available for a leadership role under these circumstances, so would I. Though if the party's actually listening to their candidate and not just playing puppeteer, that debate looks like it may be going through anyway.