Once my friend happened to talk to a foreigner in Saudi Arabia. My friend asked him how many Musims you have in your country. He said NONE. My friend inquired are they all non-Muslim? He said NO. Seeing him perplexed he inquired whom you call a Muslim?
My friend said the one who abide by Divine Laws is a Muslim. He said that mean he is a Muslim to ratio of the number of Divine Laws he obeys. My friend said Yes perhaps. Now tell me who is a non-Muslim he inqired. My friend said the one who does not obey divine laws. He said then that mean he is a non-Muslim to the extent the number of divine laws he disobeys. So it is clear none is 100 percent Muslim and none is 100 percent Non-Muslim, so long as they believe in their Creater. The one who does not believe in the Creater is neither a Muslim nor a Non-Muslim. He is an atheist.
I am very confuse strong arguments required

well no strong arguments required, it is very strange that the definition that your friend gave was the same for that foreigner...actually i think it is a biggest coincidence that both have strong definition for a Muslim and non Muslim...
ok let us assume that it might have happened...
the problem is only in definition of a Muslim and non muslim that your friend gave...this is wrong that those who abide by the divine laws are Muslims to the extent they follow these laws and same for non Muslims...
correct definition is that a muslim is one who testify from heart that Allah is the one, Prophet (PBUH) is the last prophet of Allah, have faith in resurrection/day of judgement, faith in angels, prophets...etc...and believing that whatever is happening is with the order of Allah and creation can do nothing on its own...
you can refer to EMAN E MUFFASSIL and EMAN E MUJMIL for the defintion of muslim dear...
if a person abides by divine laws but does not fulfill all aforementioned conditions, he will get no sawab as he is kafir...and same goes for a muslim, if he abides by them then he will be rewarded and vice versa...

Allah will judge people not on what they knew [yalamun], He will judge people on what they did [yamalun]. Only truth makes a difference. But truth may be useless if it is useless truth, I mean truth that we cannot use. If you cannot spend your gold in your pocket you can’t be rich. Knowledge that we cannot use will not make us wise. So what happened to that knowledge that Muslims already have?
Allah did not create us perfect. We are all going to fall short
sometimes and fail to uphold all the divine laws. Either due to
ignorance, coercion, oppression or our own ego (selfish desires, pride,
inner demon, satan). Allah in his wisdom describes himself as merciful
and forgiving. He understands our nature better than we do. Afterall, he
created it!
What Allah expects from us as Muslims is to strive and struggle to be
better. Growth (self development) is dependent on active struggle. It is
a deep yearning and desire to be better in all aspects of our lives. It
is a never ending pursuit to copy and mimic just like Allah's awesome
attributes in intellect, character, conduct, creativity and personality.
Fortunately, Allah has provided us with the guidelines to acheive this
in his book, the Quran, and gave us perfect examples, in the messengers
he sent to humanity. This is what Allah expects from us at the personal,
or individual level. He expects an impeccable character, blameless
conduct and an ever curious intellect always seeking the truth. It
takes of life time of study, devotion and practice to emulate Allah's
qualities.
At the broader level, Allah expects 2 things from Muslims.
1) The unification of humanity (regardless of our differences)
2) The creation of utopias (perfect systems, organizations, structures,
families, communities societies, countries and nations) based on the
divine wisdoms found in the Quran.
So by what standards should you judge yourself as a Muslim? We need to
ask ourselves the following questions if we aspire to be mature Muslims.
1) What are we doing daily to improve our conduct and character (in
particular, our interaction with the creations of the universe (both
hostile and friendly) and universe itself)?

2) What are we doing to unify humanity so we can focus on our common
responsibilities and heritages as opposed to our superficial
differences?

3) What are we doing to create perfect systems,organizations,
structures, families and communities based on the divine wisdoms found
in the Quran.

In my humble opinion, I think these are criteria we should use to judge
ourselves as Muslims as opposed to how many divine laws we are obeying.
The reality is that it'll be difficult and sometimes impossible to
follow all the divine laws if we do not create the environment that
makes it easy for every creation to do so.
.
May Allah guide us to the best path.

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LOVE all, TRUST a few, do WRONG to none......

There must not be any confusion.

Muslim is the one believes in Allah, His angels, His books, His Prophets and the Day of Judgment. Momin is the one who abides by the Divine Laws.

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The Me you have always known, the Me that's a stranger still.

no doubt