The claim going around is that the US gunned down the drug runners in the water that had survived the initial attack. That claim has been debunked. Even the anti-Trump leftist rag, the New York Times, acknowledged that, that didn't happen.
The military and Coast Guard are following all rules of engagement.
The "war" was declared on Venezuela's drug manufacturing and running businesses, not on the nation itself.
However, perhaps the US should go into Venezuela. Maria Machado actually won the primary election in Venezuela, but the Maduro Communist government refused to accept her win. That's what Communist authoritarian governments do.