Even if they had the right to call themselves a Khilafah and one of their rulers committed acts of disbelief then the validity of the Khilafah would be null, even Abu Bakr :ra: acknowledged this as did the other rightly guided Caliphs.
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I call for nothing more than Tawhid and that is the essence of Islam, so it is rather your understanding of the deen is corrupt.
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And Allah said in his speech:
وَٱلَّذِينَ ٱتَّخَذُوا۟ مَسْجِدًا ضِرَارًا وَكُفْرًا وَتَفْرِيقًۢا بَيْنَ ٱلْمُؤْمِنِينَ وَإِرْصَادًا لِّمَنْ حَارَبَ ٱللَّهَ وَرَسُولَهُۥ مِن قَبْلُ ۚ وَلَيَحْلِفُنَّ إِنْ أَرَدْنَآ إِلَّا ٱلْحُسْنَىٰ ۖ
And there are those who put up a mosque by way of mischief and infidelity - to disunite the Believers - and in preparation for one who warred against Allah and His Messenger aforetime. They will indeed swear that their intention is nothing but good; But Allah doth declare that they are certainly liars.
Surah Tawbah Ayah 107
(If we come back from our travel, Allah willing.) When the Messenger of Allah came back from Tabuk and was approximately one or two days away from Al-Madinah, Jibril came down to him with the news about Masjid Ad-Dirar and the disbelief and division between the believers, who were in Masjid Quba' (which was built on piety from the first day), that Masjid Ad-Dirar was meant to achieve. Therefore, the Messenger of Allah sent some people to Masjid Ad-Dirar to bring it down before he reached Al-Madinah. `Ali bin Abi Talhah reported that Ibn `Abbas said about this Ayah (9:107), "They are some people of the Ansar to whom Abu `Amir said, `Build a Masjid and prepare whatever you can of power and weapons, for I am headed towards Caesar, emperor of Rome, to bring Roman soldiers with whom I will expel Muhammad and his companions.' When they built their Masjid, they went to the Prophet and said to him, "We finished building our Masjid and we would like you pray in it and invoke Allah for us for His blessings
Tafsir ibn Kathir on 9:107
قال ابن قيم "لا يجوز إبقاء مواضع الشرك والطواغيت بعد القدرة على هدمها وإبطالها يوما واحدا فإنها شعائر الكفر والشرك وهي أعظم المنكرات فلا يجوز الإقرار عليها مع القدرة البتة."
Ibn Qayyim :rahm: said: It is not permissible to keep the positions of shirk and tyrants after the ability to destroy them and invalidate them for one day, for they are the rituals of kufr and shirk, which are the greatest evils.
Narrated 'Aisha:
When the Prophet became ill, some of his wives talked about a Ethiopia and it was called Mariya. Um Salma and Um Habiba had been to Ethiopia, and both of them narrated its (the Church's) beauty and the pictures it contained. The Prophet raised his head and said, "Those are the people who, whenever a pious man dies amongst them, make a place of worship at his grave and then they make those pictures in it. Those are the worst creatures in the Sight of Allah."
Sahih Bukhari