Sure; but so is pretty much anything we do with animals.

Is it worse than the cattle industry? Worse than re-introducing wolves to Yellowstone? Worse than engineering mosquitoes to be sterile? They all have their cost.

This cost is measured in African elephant abuse. A sound argument. The ecosystem argument, not so much as they also elaborate competently on.

Let's admit, the single reason to 'bring back' the Mammoth is, it's cool and a tremendous publicity scheme for ecological efforts. That alone, may be reason enough.

And, anything that brings in the dollars is going to happen. Argue all you want, about ecology and seed dispersal and other 'real' effects. The money a Mammoth park would bring, the imaginations stimulated and the youth inspired, could be worth it all on it's own.

Arguably, the only good conservation involves removing all humans forever. Given how that’s not a workable or good idea (from a self-preservation perspective) everything else is open to interpretation.

(Not an argument for maximalist interpretations)

What is bad about engineering mosquitos to be sterile?

The conservation biology world has some interesting philosophical problems to wrestle with.

On one hand, despite the best efforts, biodiversity loss is accelerating. We're losing habitats and species faster than earth has seen in 60 million years. Ecosystems are so degraded that they require intervention.

On the other hand, what sort of intervention is appropriate? Are we trying to conserve things as is today, or restore to a vision of the pre-industrial landscale, or the pre-agricultural landscape? Or do we try to build a new ecosystem to handle anticipated climate shifts? Do we introduce new species? Do we focus on all biomass, just flora or fauna, insects, fungi too? Do we bring back extinct keystone species like the mammoth?

There is no ethical compass that can tell us the "right" intervention.