I watched last week's episode of Question Time and didn't think Fiona Bruce said anything wrong, let alone trivialise domestic violence. What she seemed to me to be doing was clarify and add context to a comment from Yasmin Alibhai-Brown, who called Stanley Johnson a wife beater. But the internet people are enraged and Fiona Bruce has stepped down from her role with a domestic violence charity.

Both these links include a clip of the relevant part of the programme.

Fiona Bruce to leave charity role after Stanley Johnson domestic violence comments

... But following the events of last week, I have faced a social media storm, much of which mischaracterised what I said and took the form of personal abuse directed at me ...
BBC Question Time host Fiona Bruce says she will step back from role as ambassador for charity Refuge after she was accused of 'trivialising' domestic abuse over Stanley Johnson 'wife-beater' claims