It is trivial for "the other side" to find a bad interpretation to any slogans. This is why slogan writers need to be very careful. In the case of "defund the police" the worst "other side" interpretation is easier to understand than what is intended. For other slogans "the other side" will make a point that looks contrived.

It is possible for anyone to see that something is a bad slogan, and easy once you have hindsight. I have no idea how to write a good one.