The legal basis is there to protect wildlife from man-made disruption and provides a kind of ecological basis to limit the kind of boundless growth that politicians appeal to.
Unfortunately, for those laws to be effective, they have to be strong enough to beat the various legal shenanigans / loopholes which can be used by developers to effortlessly leapfrog them.
Finally, if the laws are strong enough, they might be effortlessly wielded to prevent even reasonable developments from occurring.
The law lands somewhere in the middle and I think there are always people at either extreme trying to take advantage.
