Despite their threatening language, the Americans also know that a military attack on North Korea is not possible. Hitting military targets leads to the death of thousands of civilians.
North Korea would make an inferno in South Korea, not with ballistic missiles, but with its colossal arsenal of ordinary old-fashioned artillery. The Korean Peninsula will simply be swept away from the map.
Classical rhetoric - possibly military intervention, more sanctions, further isolation, diplomatic pressure - does not produce anything. China and Russia demand America to stop joint military exercises with South Korea, and remove the THAAD anti-missile system from South Korea, but that would not help.
Bombs do not solve the issues; Sanctions do not help, diplomacy does not work either. Then what? The answer is: deprive North Korea of one of its main sources of income, the slavery. It is estimated that at least 100,000 North Koreans work as slaves in Russia, China and other Asian countries, but also in Europe. In St. Petersburg, North Korean slaves worked as construction workers at the Football / Soccer World Cup stadium in 2018. The FIFA knows this, and does not say more than an occasional stinging statement "we made our concerns clear".
The slaves also work in the European Union. The Czech Republic has terminated guest employment contracts for North Koreans, but other Eastern European countries - such as Poland - did not. An ongoing study by Leiden University (Netherlands) also refers to Western Europe, perhaps even the Netherlands.
How does it work? North Korea - through foreign governments - signs contracts that fully meet international criteria on paper. For temporary work in eg construction projects, a normal salary is paid with standard working conditions. In reality, North Korea keeps employees passports, collects salaries directly or forces workers to submit, slaves work seven days a week and 12 hours a day, sit behind barbed wire, be supervised by slave drivers and be arrested with continued threat to their family in North Korea. If the slaves violate the rules or try to escape, their government takes revenge on their families.
Perhaps when starting a real campaign against North Korean slavery, we are likely to reach our goals more than the impractical threats with a military attack or sanctions that do not work. Hitting North Korea on financial grounds - by tackling slavery - choose the path of decency, has a significantly higher chance of results the western world wants.