"even though it's against Quran"
Why do you believe it's against the Qur'an?IMO, even though it's against Quran [30:32], maybe it's time to do positive advertising, if each sect want to promote his. Allah knows best.
unless we have a bullet-proof evidence(repeat 10x), then i find the following as thought provoking (at least it appears to be so to me).
[Shakir 25:30] And the Messenger cried out: O my Lord! surely my people have treated this Quran as a forsaken thing.
1. Be not disunited
[Shakir 3:103] And hold fast by the covenant of Allah all together and
be not disunited, and remember the favor of Allah on you when you were enemies, then He united your hearts so by His favor you became brethren; and you were on the brink of a pit of fire, then He saved you from it, thus does Allah make clear to you His communications that you may follow the right way.
2. When we are disunited
2.1 Prophet saww has no concern
[Shakir 6:159] Surely they who divided their religion into parts and became sects,
you have no concern with them; their affair is only with Allah, then He will inform them of what they did.
2.2 don't rejoice with what we have
[Shakir 30:31] Turning to Him, and be careful of (your duty to) Him and keep up prayer and be not of the polytheists
[Shakir 30:32] Of those who divided their religion and became sects, every sect rejoicing in what they had with them
2.3 Don't worsen the situation, mocking each other. instead, let's race with one another to virtuous deeds.
[Shakir 5:48] And We have revealed to you the Book with the truth, verifying what is before it of the Book and a guardian over it, therefore judge between them by what Allah has revealed, and do not follow their low desires (to turn away) from the truth that has come to you; for every one of you did We appoint a law and a way, and if Allah had pleased He would have made you (all) a single people, but that He might try you in what He gave you,
therefore strive with one another to hasten to virtuous deeds; to Allah is your return, of all (of you), so He will let you know that in which you differed;
3. If your are a leader
[Shakir 16:25] That they may bear their burdens entirely on the day of resurrection and also of the burdens of those whom they lead astray without knowledge; now surely evil is what they bear.
4. If you are a follower
4.1 Don't follow blindly: we may be facing intense regret then.
[Shakir 2:166] When those who were followed shall renounce those who followed (them), and they see the chastisement and their ties are cut asunder.
[Shakir 2:167] And those who followed shall say: Had there been for us a return, then we would renounce them as they have renounced us. Thus will Allah show them their deeds to be intense regret to them, and they shall not come forth from the fire.
4.2 Don't obey a sinner
[Shakir 76:24] Therefore wait patiently for the command of your Lord,
and obey not from among them a sinner or an ungrateful one
5.0 Munafiq
[Shakir 63:4] And when you see them, their persons will please you, and If they speak, you will listen to their speech; (they are) as if they were big pieces of wood clad with garments; they think every cry to be against them. They are the enemy, therefore beware of them; may Allah destroy them, whence are they turned back?
Allah Knows Best.