whats it held together with? looks like the materials used are sturdy enough. maybe just run some 3.5"deck screws into the joints to secure them better. that thing shouldn't wobble unless the screws or nails or whatevers holding it together just arent anchored firmly.
Just bc its wobbly doesnt mean it won't hold... those double metal stands are all very wobbly lol... if the whole rack as a whole is wobbly you should be fine if it's individual wood pieces that are wobbly I would add a few extra screws