I think one may liken the concept to joining a club. If you do not like the rules, don't join. To recieve the greatest promise on offer, ascension to heaven after death, one must accept Jesus and undertake to obey the rules. God makes them up and we do not have to like them. A sinner on the cross repented and was told he would be with Jesus in Paradise today. Hence God is very mercifull.
If you don't cut it in this life, then you'll get another chance in the resurection of the dead.
The biggest fallacy is many faiths have an over developed sence of self importance and believe they get to change the rules as it suits them eg pope who declared himself omnipotent. Christians do not get to change the rules eg fornication, adultery, homosexuality.
The bible is very clear that God is very jealous. You cannot bow down to any other God. If you accept Jesus and try to show this through works, I do not think it matters what faith you call yourself or even if you align with none in particular.
Jesus told his people to obey the law in so far as it does not compromise Gods word. He called the religious leaders sons of vipers and from their father the Devil and told people not to emulate their excesses of greed and places of honour at the table.
Is it fair? Does it suit you? Do we see things differently?...is all irrelevant because God gets to make the rules and has the power to enforce them. We cannot argue our way into heaven.
Not all Christians believe in the exclusivity clause.