Gadolhadorah, halacha is supreme to secular law. But, as you said, just because someone can do something according to halacha doesn’t mean they should take advantage of that.
Imagine if I as a mother would “take advantage” of the laws of kibud eim and force one of my children to cook, clean the entire house and wash the laundry every day because my daughter would be obligated to do so according to halacha. That is abuse plain and simple.
Now I forgot to add in my previous comment to ujm, that although individuals have “rights” according to halacha, we also have halachic “obligations”, so for example, we cannot cause pain for others. So when people disregard an halachik obligation to take advantage of an halachik right, they will go to gehinom for trampling on halacha, especially if it was bein adom lachveroy.