Obviously, we humans have no right to destroy other species' habitats or natual homes and kill them for our interest, especially the illegal trade.
Here are sufficient reasons to support my point of view.
Firstly, every life-form has a right to exist, and that no other reason is needed for preserving it. Certain species have economic value. Besides, about 15 percent of all our medicines are derived from tropical plants. And we also can learn from the animal or plant and get idea to make new instruments.
Secondly, we are a part of the ecosystem. In the long time of evolution, we defeat other species and become the dominator of the earth. However, we have no right to decide other species' death. Humans kill off animals just to satisfy the desire of human' need. Consequently, it is caused by human activity that many species have died out.