why is neonatal male circumcision not popular in Europe like it is in America?

Because the USA has a privatised fee for service medical system.

In the U.K. the rate of circumcision dramatically fell with the introduction of the National Health Service.

It has very little to do with religion. Jewish people and Muslims have religious reasons for circumcision. Historically Christianity opposed routine male circumcision until the 19th century. Then it came into favour in an attempt to stop masturbation.

Because there is no valid reason for neonatal circumcision. If there are medical problems that require circumcision, such as phimosis, these do not usually show up before the boy is 7-9 years old. Widespread male circumcision for non-religious reasons as is seen in the USA was thought to stop boys masturbating. It didn't, of course, but that didn't stop the practice continuing. It is only in recent years that automatic circumcision of neonates has stopped. It never started in Europe except for religious reasons.

Because the idea that bible god designed the penis wrong is more popular in bible god believing countries.

Because the influence of the Catholic Church was stronger in Europe then as generations past you ended up with a bunch of uncircumcised guys that were self-conscious about it but did not want to get circumcised so they made up some stupid cause against circumcision.