INQ,
You are correct is saying that there are similarities in most religions. But to the sincere JW, the WT doctrine is original and exclusive. Since JWs are close minded to other religions, they fail to see that the WT doctrine and practices are not always all that different from "false religion" as they might like to believe. If JWs were 'allowed' to study or involve themselves with other religions, in this case Islam, they may longer view the WT as having the monopoly on all things considered spiritual truth.
You are not familiar with Islam. It is not accurate to associate everything "Muslim" per se with Islam.
And for your information Islam does practice a form of shunning against their version of apostates. This can be seen in some Islamic families where one family member abandons Islam for the teaching of infidels. The family will not execute the person but rather disown him.
Like the WT, Islam also encourages "preaching"... " Invite to the way of your Lord with wisdom and beautiful preaching." Al' Quran 16:125... Sura Al-Nahl 16, Ayah 125.
Here are just a few more similarities between Islam and the JW world.
1. Associating partners with Allah (shirk). Allah Most High says (in the meaning):