Perhaps the "defund" is so entrenched in the conservative playbook as meaning "eliminate by starving of operating capital" that using "defund" to mean "free up capital to be re-prioritized to other social causes" simply seems nonintuitive or alien to them.
also, the dictionary definition of 'defund' means "to withdraw funding from"
if you wanted to campaign on partially defunding the police, then you'd get a different reaction.
i'm not aware of any previous major political movements which used the slogan 'defund X' to mean 'partially reduce funding to, but continue to support sufficiently to ensure proper functioning of X"
so if (a) defund doesn't imply "partially reduce funding" and (b) the word defund has not historically been used that way and (c) plenty of activists say "literally abolish the police" [1] then if people are failing to interpret it the way you'd like, the burden is on proponents to have a better slogan to communicate their message
