It is not, because the “police reform” movement of the last several decades that drives more funding for retraining and additional resources to police in the name of correcting the exact same problems “defund the police” sellar to address is exactly what they are diametrically opposed to and a reason against, and blame for exacerbating the problem by further draining resources from other local services and leading to police taking even more responsibilities outside of their core competencies.

I mean, sure, in a context-free sense, yes, what they seek is, or includes, reform of policing, but that slogan has existing loading in the current context and it's something the group in question defines themself on opposition to, so no, it's not a perfectly fine slogan, any more than “pro-life” would be for a movement for robust publicly funded universal healthcare including comprehensive reproductive health coverage.

Situation: half the country wants to enclose the country in a giant styrofoam bubble to keep people out. The other half wants to import foreigners at gun point.

Conclusion: We have 100% popular support for immigration reform! Why can't those layabouts in government make it happen?