Muslims are persecuted because they have given up Jihad, fighting for their defense and strengthening themselves militarily.
This is in the Quran in 2:195 and 9:39 which warn of punishment and destruction for not engaging in Jihad.
This has been also told in several hadith such as which prophecy that Muslims will be disgraced and subjugated as they will stop Jihad and will cultivate love for this world:
حَدَّثَنَا سُلَيْمَانُ بْنُ دَاوُدَ الْمَهْرِيُّ، أَخْبَرَنَا ابْنُ
وَهْبٍ، أَخْبَرَنِي حَيْوَةُ بْنُ شُرَيْحٍ، ح وَحَدَّثَنَا جَعْفَرُ
بْنُ مُسَافِرٍ التِّنِّيسِيُّ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يَحْيَى
الْبُرُلُّسِيُّ، حَدَّثَنَا حَيْوَةُ بْنُ شُرَيْحٍ، عَنْ إِسْحَاقَ
أَبِي عَبْدِ الرَّحْمَنِ، - قَالَ سُلَيْمَانُ عَنْ أَبِي عَبْدِ
الرَّحْمَنِ الْخُرَاسَانِيِّ، - أَنَّ عَطَاءً الْخُرَاسَانِيَّ،
حَدَّثَهُ أَنَّ نَافِعًا حَدَّثَهُ عَنِ ابْنِ عُمَرَ، قَالَ سَمِعْتُ
رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " إِذَا تَبَايَعْتُمْ
بِالْعِينَةِ وَأَخَذْتُمْ أَذْنَابَ الْبَقَرِ وَرَضِيتُمْ بِالزَّرْعِ
وَتَرَكْتُمُ الْجِهَادَ سَلَّطَ اللَّهُ عَلَيْكُمْ ذُلاًّ لاَ
يَنْزِعُهُ حَتَّى تَرْجِعُوا إِلَى دِينِكُمْ " . قَالَ أَبُو
دَاوُدَ الإِخْبَارُ لِجَعْفَرٍ وَهَذَا لَفْظُهُ
Narrated Abdullah ibn Umar:
I heard the Messenger of Allah, (Peace be upon him) say: When you
enter into the inah transaction, hold the tails of oxen, are pleased
with agriculture, and give up conducting jihad (struggle in the way of
Allah). Allah will make disgrace prevail over you, and will not
withdraw it until you return to your original religion.
حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ إِبْرَاهِيمَ الدِّمَشْقِيُّ،
حَدَّثَنَا بِشْرُ بْنُ بَكْرٍ، حَدَّثَنَا ابْنُ جَابِرٍ، حَدَّثَنِي
أَبُو عَبْدِ السَّلاَمِ، عَنْ ثَوْبَانَ، قَالَ قَالَ رَسُولُ اللَّهِ
صلى الله عليه وسلم " يُوشِكُ الأُمَمُ أَنْ تَدَاعَى عَلَيْكُمْ كَمَا
تَدَاعَى الأَكَلَةُ إِلَى قَصْعَتِهَا " . فَقَالَ قَائِلٌ وَمِنْ
قِلَّةٍ نَحْنُ يَوْمَئِذٍ قَالَ " بَلْ أَنْتُمْ يَوْمَئِذٍ كَثِيرٌ
وَلَكِنَّكُمْ غُثَاءٌ كَغُثَاءِ السَّيْلِ وَلَيَنْزِعَنَّ اللَّهُ مِنْ
صُدُورِ عَدُوِّكُمُ الْمَهَابَةَ مِنْكُمْ وَلَيَقْذِفَنَّ اللَّهُ فِي
قُلُوبِكُمُ الْوَهَنَ " . فَقَالَ قَائِلٌ يَا رَسُولَ اللَّهِ
وَمَا الْوَهَنُ قَالَ " حُبُّ الدُّنْيَا وَكَرَاهِيَةُ الْمَوْتِ "
The Prophet (Peace be upon him) said: The people will soon summon one
another to attack you as people when eating invite others to share
their dish. Someone asked: Will that be because of our small numbers
at that time? He replied: No, you will be numerous at that time: but
you will be scum and rubbish like that carried down by a torrent, and
Allah will take fear of you from the breasts of your enemy and last
enervation into your hearts. Someone asked: What is wahn (enervation).
Messenger of Allah (Peace be upon him): He replied: Love of the world
and dislike of death.
I mean Jihad in the sense of Qital with arms. That is the proper meaning of Jihad in over 99% of the cases.
Qital is Farz on every Muslim, this is in 2:216 where it has been prescribed كُتِبَ , it is Farz Ayin when it is for defending Muslims. It is Farz Kifaya when it is for expansion, but that is not relevant here. See tafsir:
In this Ayah, Allah made it obligatory for the Muslims to fight in
Jihad against the evil of the enemy who transgress against Islam.
Az-Zuhri said, "Jihad is required from every person, whether he
actually joins the fighting or remains behind. Whoever remains behind
is required to give support, if support is warranted; to provide aid,
if aid is needed; and to march forth, if he is commanded to do so. If
he is not needed, then he remains behind.'' It is reported in the
«مَنْ مَاتَ وَلَمْ يَغْزُ وَلَمْ يُحَدِّثْ نَفْسَهُ بِالْغَزْوِ، مَاتَ
(Whoever dies but neither fought (i.e., in Allah's cause), nor
sincerely considered fighting, will die a death of Jahiliyyah
(pre-Islamic era of ignorance).)
On the day of Al-Fath (when he conquered Makkah), the Prophet said:
«لَا هِجْرَةَ بَعْدَ الْفَتْحِ وَلكِنْ جِهَادٌ وَنِيَّةٌ، وَإِذَا
(There is no Hijrah (migration from Makkah to Al-Madinah) after the
victory, but only Jihad and good intention. If you were required to
march forth, then march forth.)
(...and that you like a thing which is bad for you.)
This Ayah is general in meaning. Hence, one might covet something, yet
in reality it is not good or beneficial for him, such as refraining
from joining the Jihad, for it might lead to the enemy taking over the
land and the government.
This means that it is Farz on every single person, including the Rohingyas and everyone else. But are the Rohingyas or anyone else fighting for the their rights?
If there are any small splinter groups doing it, they do not count for fulfilling Farz Ayin. Also logically they do not have the same power as the whole.
I'll end by quoting 4:75:
And what is [the matter] with you that you fight not in the cause of
Allah and [for] the oppressed among men, women, and children who say,
"Our Lord, take us out of this city of oppressive people and appoint
for us from Yourself a protector and appoint for us from Yourself a