Why did Muhammad want the Jews and Christians dead?

Answer 1

It is the same reason why people don't like people who oppose or argue against their beliefs and "way of life". What was revealed to Muhammad spoke against idol worship, adultery, and some issues that the Jews and Christians have.

The Qur'an discriminates harshly towards them.

Answer 2

Muhammad initially sought good relations with both the Jews and Christians. It is reported that he even sought to be named as a prophet by the local Jews but that, being rebuffed, he began to consider his own religious movement.

After Muhammad's move from Mecca to the city of Medina, two important tribes of that city rebelled against his rule and may have attempted to take over the rule of the entire city. Muhammad succeeded in driving them out and, after this, treated the Jews as less worthy than Christians. Neverthless, he saw the pagans as the real enemy of Islam.

As Islam spread, Muhammad afforded Jews and Christians protection as "people of the Book", but required pagans to convert on pain of death. The evidence of this is that paganism vanished rapidly on the Arabian peninsula, while Judaism and Christianity flourished right up until the twentieth century.

After the death of Muhammad, Jews and Christians continued to have a relatively privileged position in Islamic society. There was subtle, and sometimes very real, persecution, but the early Muslim leaders treated Jews and Christians relatively well compared to the treatment that Jews had received from Christian rulers since the time of Constantine.

At no time since the advent of Islam have Muslim religious leaders sought the wholesale slaughter of Jews or Christians.

Answer 3

Initially, the people of Mecca were generally bothered by Muhammad in much the same way that people are bothered by street-preachers today. It was an annoyance. His message became more problematic when Muhammad argued against the religious plurality in Mecca. However, violent opposition to Muhammad only began when he made clear that he intended to purge the idols from the Kaaba, effectively "killing" Non-Muslims' gods and destroying their sacred property. These kinds of threats were not well-taken.