Regulation doesn't mean "heavily discourage".
Keeping the Moon, or Mars, or Venus as pristine as possible is the only way we can study those environments as they exist in their natural condition. Not to mention that we can't detect the presence of life on those worlds if we've contaminated them with life from our own.
If you think this idea is incompatible with exploration, you can take it up with NASA's Office of Planetary Protection:
Why is this more important than expanding our ability as a species to explore space?