There are tens of thousands of voters who don't have children but have a cat or a pet of some kind. Vance's comments seem to double down on many of Trump's previous vile comments and policies from both his time on the campaign trail and as president. Republicans have just insulted a large constituency that could seriously impact the vote in swing states.
Democrats have blatantly taken Vance's comments out of context. Republicans are fighting for the forgotten working-class women of the US, and Democrats are trying to distract attention from their anti-family policies that have tanked the American dream. Republicans know they'll have to continue pushing back against fiction for the remainder of the campaign.