Everything has real negative consequences. One side does not hold the monopoly on negative side effects.
Land is not cheap to repurpose. The Georgism dream that land can be optimally used is a farce. There is significant costs to repurposing land - to make those costs worth it because of the taxes would heavily distort current society, and I think the assumption that this would be desirable compared to the status quo is unproven.
> double sales tax? Or increase income taxes?
Why not the taxes we have? Where is the presumption that taxes need to be changed at all, never mind doubled?
Even if we decide we want to raise taxes, choosing where to do so is delicate. Again, the optimal answer from an economist is not necessarily desirable from an emotional perspective of the people being governed.