I think the actual truth lies between both scorpion and ramis answer. Firstly a woman must wear 'hijab' its obligatory its really as simple as that. Fully covered including face or just head? Well that’s debateble and comes down to mans interpretation of the verse. However majority of the prove does lie in covering the face (which I will explain to a muslim in pm if necessary).
The matter of bringing up verses need to be accompanied with the prophetic sayings and exegis for it to be regarded fully understandable, therefore its not right for the matter to be taken word by word. Sticking to the topic, the holy prophet pbuh also prophecised that those who don’t cover themselves amongst (non related men) will find themselves in hell. Now those who dont wear it are they muslims? yes of course. But hang on a sec have I contradicted myself? Er no. Why simply because they remain muslims till they die (unless if they commit polytheism), but if they continue to do such forbidden acts and being rebellious in islam then they will die as non muslims. Rami used the right words when he said they are munafiq (hypocrites) or most possibly faasiq (rebellious). The punishment for such people is worse than many non muslims, simply because they knew the truth and didnt go by it. What islam encourages is for a muslim to follow its rules.
In an islamic country governed by shariah such rules are given punishment if they are broken, i.e hand chopped if one steals. These laws were inherently passed down. However there is no real punishment on earth in terms of shariah if a woman doesnt wear hijab, but overall it does bring disorder in teh country is disliked amongst many scholors if not all. Such disorder can leader to serious concequences such as rape or adultery. Note that adultery is a major crime in islam.
Moving on, as for the matter of being judgemental or not, this is where you can be judgemental but obviously not to a certain extent where you call a muslim a non muslim. This is a sacred issue and one who does so has indeed violated his own belief and commited disbelief. However as scorpion said the real way to go out about it is to condemn the action rather than condemning the person. "Enjoin good forbid evil". This is a famous saying amongst the elite of scholors. Therfore you should praise a person for the righteousness and speak out against such evil that he may be doing but speak out against the action rather against the person. I would just like to highlight the differenece here humans are mistake prone, infact in general very gullible, which is what islam understands, that’s why one is not allowed to have a go at the person but rather at what he beliefs. However islam also recognises the emotional state of a human being and thus doesn’t encourage anyone and everyone to have a go at a persons way of thinking but rather encourages who is knowledgable. Also the approach has to be in a polite and in an informative manner, the way just like the prophet pbuh did. He chose the best and precise of words with politeness to ensure the message is drawn across.
If a person still refuses then by reality islam recognises this and does not go against a persons wish and force them to do anything or forbid them to do anything.
Many muslims are unaware of what there own religion teaches which is why islam encourages the muslim to go and seek knowledge and spread it.
As for the point that ze tahir made regarding christianity being monotheistic... well I dont really know about that when in reality both "jesus and his father are divine everlasting beings". nauzobillah. Infact they are both called “god”. Christianity has no doubt become a very lenient religion, infact hardly anything is compulsory.
As for the matter of what god requires..
Lets not forget first what sort of punishment god has said that will be given to those who disbelief. This punishment will be severe, one that which is unimaginable. Imagine yourself standing on the sun for eternity, quenching yourself for water, the only source of food is that from a cursed tree and only source of water is that from yourself. It sounds like a fairy tale for many non muslims but what god encourages in the quran is for everyone to take note both muslim and non muslim. Now everyone is responsible for their own action and one things for sure god has given free will to man, but in reality if man was to think for himself then he should know that he should be obeying god’s orders, because not everything lasts forever.
The above paragraph is a general overview for non muslims.
Now when you are a muslim, the responsibilities are greater, by saying the tawheed ( believing in monothism) isn’t simply it. Infact to be precise just saying it doesn’t mean anything, to have intent, understand what it means and understand its principles e.t.c is what makes a muslim. To be exact, this is what a muslim should believe his god is, and if he doesn’t then he certainly aint a muslim.
"Say! He is God, the One!
The Eternally Besought of all!
He does not beget, nor is He begotten.
And there is nothing comparable to Him." (Quran)
A muslim is required obligatory to do the five pillars and those who don’t even pray their five prayers are already away from islam. They will get punishment for that and if they die in a state of disbelief (which can easily happen) then they themselves will spend their time in hell. So its obviously a serious issue but that which is very simple once understood and practised. For those who condemn your own religion without even knowing where the truth lies is seriously looked down upon, not only by scholors but also by god. Its almost goes to the certain realm of mocking your own religion or rather reknowned to be known as blasphemy, which is serious. These people certainly do need to be judged and condemned upon, reason is because such people will end up spreading the wrong image of islam. And the reality is im afraid many people have exactly that.. the wrong image..
As for the question regarding whether islam teaches everyone should be a muslim. Well yes islam was brought down for all mankind, its as simple as that, if you don’t believe, you will get punished. However both man and his satan are to blame for that.
This is my two cents..
I would just like to say that as this is a football forum, this debate shouldn’t really go further, unless if its okay with the moderators. If necessary I would rather take this somewhere else and if anyone is interested to either find out more or prove me wrong then please pm me and I shall arrange a time and place for such a debate as this is a serious matter which I hold deeply.
Above all Allahualam.