I think it comes, and gets due frustration, because of the high willingness to entertain calls to defund schools, the post office, the EPA, transportaition, housing, Health and human services, veterans affairs, Medicaid, food stamps etc etc etc.
so many have openly embraced defunding these beneficial programs but when you bring up the reality that our police force is not functioning as it should and call to address some of the egregious spending and misappropriation of funds and efforts there using the word "defund" it's now completely unthinkable
but you're right, it's to easy to twist that term into an image of impossible anarchic lawlessness as opposed to a real proposal, and police are a force which affects us all tangibly, whereas the impact of say not having a properly funded EPA might seem a positive even for people who want that sort of lawlessness that allows them to destroy the planet, versus the possibility of allowing "others' to destroy/steal their own immediate possessions