Extremism, fanaticism, and bigotry are nothing but qualities that are basically forbidden by the right religion. The Noble Qur’an urges people in many verses to be gentle and merciful, pardoning and forgiving.
Allah Almighty said:
{It is by Allah’s mercy that you [O Prophet] became lenient to them. If you had been harsh and hard-hearted, they would have dispersed from you. So pardon them, seek forgiveness for them, and consult them in the important matters. But once you have made a decision, put your trust in Allah, for Allah loves those who put their trust in Him.} [194] Surat Āl ‘Imrān: 159.
{Call to the way of your Lord with wisdom and goodly exhortation, and reason with them in the best manner. Your Lord knows best who has strayed from His way and knows best those who are rightly guided.} [195] Surat an-Nahl: 125.
Lawfulness is the basic rule in Islam with the exclusion of a limited number of prohibitions, which are indisputable and clearly mentioned in the Noble Qur’an.
Allah Almighty said:
{O children of Adam, dress well for every prayer. Eat and drink, but do not waste, for He does not like the wasteful. Say, “Who has forbidden the adornments and lawful provisions that Allah has brought forth for His slaves?” Say, “They are for the believers in the life of this world, and they will be exclusively for them on the Day of Resurrection. This is how We make the verses clear for people who have knowledge.” Say, “My Lord has forbidden shameful acts done openly or in secret, sinfulness, unjustified aggression, associating partners with Allah for which He has not sent down any authority, and saying about Allah that of which you have no knowledge.”} [196] Surat al-A‘rāf: 31-33.
Islam has described as demonic acts all what calls to extremism, fanaticism, or prohibition without a Sharia-valid evidence, and religion has nothing to do with them.
Allah Almighty said:
{O people, eat from what is lawful and good on earth and do not follow the footsteps of Satan, for he is your sworn enemy. He only orders you to commit evil and immoral deeds, and to say concerning Allah what you do not know.} [197] Surat al-Baqarah: 168-169.
{And I [Satan] will surely mislead them and arouse in them false hopes, and will order them to slit the ears of livestock, and will order them to change Allah’s creation.” Whoever takes Satan as a protector instead of Allah has surely suffered a manifest loss.} [198] Surat an-Nisā’: 119.