Preserve your sanity in a VC meeting by these methods:
Introduce ground rules in the meeting requesting it to be free of negative talk, on the pretext of detoxing the audience/team members and improving their mental health.
Intentionally keep things positive, promoting sharing of positive things and ending the meeting on a high note, so that the negative is by default kept out, without pinpointing it.
In case a higher-up or a boss is the one with the negative talk, one can bite the bullet and request the person personally and politely to stop or reduce the negative banter.