They may be wrong, but with the way common law works, a lot of judges are obliged to judge in accord with their reasoning.
As for the phrase "only interpret it", the way the law is interpreted bears so little relation to what is written that there is no "only" about it. For the most obviously extreme example, consider how radically the interpretation of the phrase To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes changed in the 1930s.
If you're unfamiliar with that history, the short version is that Congress went from being able to regulate direct trade crossing state boundaries to being able to regulate anything that relates to commerce, even indirectly. For instance the Civil Rights Act is legal because of the Commerce Clause. I like the outcome, but do not agree with the reasoning used to get there.
As for the phrase "only interpret it", the way the law is interpreted bears so little relation to what is written that there is no "only" about it. For the most obviously extreme example, consider how radically the interpretation of the phrase To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes changed in the 1930s.
If you're unfamiliar with that history, the short version is that Congress went from being able to regulate direct trade crossing state boundaries to being able to regulate anything that relates to commerce, even indirectly. For instance the Civil Rights Act is legal because of the Commerce Clause. I like the outcome, but do not agree with the reasoning used to get there.