Thank you for your honest Question. I hope I understood it completely as I am trying to answer this with my limited knowledge,
Can one be a Muslim and not follow all the rules of Islam?
Is same as Can one be a Docter without Degree? Sure I can put on a white coat and operate on people but lets not get into what will happen to the patients.
Lets Discuss what a Muslim is first,
A Muslim is one who submits to God. Submitting to God to a Muslim is submitting to infinite wisdom and sum of Knowledge. Submitting to the love and care of the Creator. Trusting the will of the Creator. Knowing EVERYTHING happens for the good. This is a what a Muslim believes in,
1) BELIEF IN ONE GOD (not 3 , not 5, not 10 or more) God the spectacular source. God the white light. God who loves the humble. God who forgives again and again. God who puts up with human selfishness. God who loves to give. God who is ready to appreciate service. God who loves purity of actions and speech. God who guards those who guard their prayers. God who is the sole incharge of the world. To a Muslim everything has been created by God and everyone will have to return to God. Every human being will be answerable for his own deeds and NOT others.
2) BELIEF IN THE DAY OF JUDGEMENT. This is the day when all that was hidden will be made clear. God put men on earth and men showed God who they are with their actions. Day of Judgement, God will show humans every single thing they did. There will be many who will lie to God and say put us back on earth, this time we will do great and God will reply to them "Did not my messengers warned you of what you did?" As God is very Just, Man will create his own heaven and hell with his own actions. God will NEVER be unjust. A stronger entity does not lie to a weaker entity and neither is scared.
3) BELIEF IN GOD'S ANGELS. Belief in Micheal, Gabriel etc on them be blessings. The ones who follow God's orders with perfection. Like Gabriel is the one who brought message to Mary and Muhammed and so many others.
4) BELIEF IN GOD's PROPHETS. Believing in all of God's prophets like Abaraham, Jacob, John the Baptist, Noah, Lot, Moses, Jesus, Muhammed, David etc . Believing that God selected them to spread their message as they FOLLOWED what they preached. Were vigilant in abstinance, always ready to love and serve. God's peace and blessings be up the messengers.
Similarly Muslims have other beliefs,
Now, why does a muslim follows what he follows? Muslims view God's order as pure and one leading to Peace. Essesntially for a human's good. Muslims dont drink alcohol and eat pork as this introduces bacteria of negativity in human's body. These bacteria impede human's understanding and gives birth to self righteousness/ego which inturn seeks separation from rest of humanity. Muslims dont eat other meat unless meat has been blessed with God's name and cut in a ritual practice which Muslims call "Halal" and my Jewish brothers and sisters call "Kosher". Failure to cut may introduce anger and fear of the animal in human as the dna mixes which is why my hindu brothers and sisters dont eat meat. Muslims though CAN eat pork if their survival is dependant on it. God teaches nothing but purity and people who follow God do it for their OWN good. Muslims are ordered to learn from cradle to grave. Muslims hear people complaining "Why God kills people?" and wonders "Wasnt it God who gives life" .
Muslims hear people complaining "Why the best voices are martrayed like Gandhi, Jesus, John the Baptist etc?" and wonders "Are they REALLY dead? or Are they alive and well with GOD, Perhaps we are dead and know it not" Muslims hear people complain "Why if we are made is God's image,world is so bad?" and wonders "Everything good that comes, comes from God and everything bad that comes, comes from desires of the ego" Muslims hear one atheist complaining "Why does not God do anything about all the bad happening in the World?" and another atheist complaning "So God does not like freewill and God floods the world, is this love of God?" and Muslims wonders "If these two atheists will sit down together, they will solve a riddle". Muslims hears alot of things and yet patiently perseveres. So a Muslim is AWARE and sees things for what they are. Muslim know God blesses Muslims and non-Muslims alike so Muslim utmost tries not to break a heart of human being with actions or words. Muslims know everyone is God's creation and a Muslim is in no way better then the other even though some have seen the unseen. A muslim when approaching God is humble and full of gratitude. He goes empty in mind as he knows he will disrespect God by thinking he knows alot. He has gratitude as he knows things could be way worse besides life is temporary and one has to return to God. What makes Muslim love eternity is WORSHIP OF GOD. With worship of God, Hell and Heaven will feel alike. Completing my rant in summarizing the religion of Islam, there
there are Muslims who kill. There are Muslims who have sex b4 marriage, gamble and drink alcohol. Sufis call them SO CALLED Muslims but then again who am I to judge as ever human being wether Muslim or Non Muslim will answer his own deeds. I have to care about my speech and deeds.
"There was a question earlier about a girl who converted to Islam, but felt she'd never find a Muslim man to marry her because she lost her virginity before her conversion." hmmmmm Our masters like Jesus, Muhammed and Moses never judged a woman who was not a virgin. Muhammed married widows. Alas, there is LOADS OF LIES all around the world. One must have a sincere friend.
In reality Tags like Muslims, Sufis, Jews, Christians , Hindus, Buddhists etc etc are NOT much use when God knows us through our actions. PEACE, LOVE AND BLESSINGS!