Defund can mean both, many who chanted that clarified that they meant abolish. If you wanted people to not misunderstand then use a better word that is clear, since many who were on the pro "defund the police" meant abolish the police.
I did not choose the slogan, so you'll have to bring up your complaint with someone else :)
Do you have a proposal for an equally short slogan that cannot be misunderstood, especially by the right-wing media machine? I don't believe that such a slogan exists, as pretty much every sentence can be willfully misunderstood.
If someone in power said that they intended to defund this or that government department, most listeners would reasonably infer that the speaker's intention is to get rid of that department. You're accusing people of moving the goalposts when all they're doing is taking the most straightforward, plain language interpretation of the phrase, "defund the police". It was the activists who picked the slogan, not everyone else.
It is your own fault for using a bad slogan.