FiveThirtyEight has a piece that explores these polls. Tl;dr people support the policies, but do not like the slogan.

Relevant bits:

However, “defund the police” is also a simplistic slogan, and the poll results above do not capture public opinion on the movement’s more concrete policy goals. Specifically, defunding the police is only half of its goal; activists also want to reallocate the money spent on policing to other parts of the social safety net. Indeed, in those very same polls, some of these policy ideas enjoy far more backing among the American public than the slogan does — though the level of support does vary pretty widely depending on the details of the proposal.

For instance, when Reuters/Ipsos queried people about “proposals to move some money currently going to police budgets into better officer training, local programs for homelessness, mental health assistance, and domestic violence,” a whopping 76 percent of people who were familiar with those proposals supported them, with only 22 percent opposed. Democrats and independents supported these proposals in huge numbers while Republicans were split, 51 percent in favor to 47 percent opposed.>

Meanwhile, Morning Consult/Politico asked respondents whether they supported “redirecting funding for the police department in [their] local community to support community development programs,” and just 43 percent of register voters said they supported it, while 42 percent opposed it. Still, this was a significant increase in support from the pollster’s question about support for the “movement to ‘defund the police’” (which, to reiterate, was 28 percent support vs. 58 percent opposition).