The difference is that in the case of Islam, the religion itself is bad, but there are some people who are good despite that.
In Sikhism, the religion itself is good, but some people in it are bad.
Right. Set free to rape the women of people you vanquished, to levy jizya on non-Muslims until they feel humiliated (quote for the Koran).
It means "submission". Submission to Holy God would be one thing, but submission to a religion that encourages violence towards non-Muslims is a bad thing.