Once a rebel is always a rebel but when there is no cause behind rebellion it almost becomes more important for society to label the rebel as without a cause but why? A rebel is concerned with norms that is a rebel wants to upstage the current norms and society counteracts by saying the rebel has no cause.
What are norms then the society is more concerned about defending? It is the aesthetic taste that society wants to defend or it could be the society wants to upturn any aesthetic taste whatsoever the current prevailing milieu endorses. The taste the rebel endorses creates conflict between intellect and imagination. So the society fears the intellect would be upstaged by a more populous taste that exists in a raw matter in much the popular sentiment in the society.
The rebel, on the other hand, wants to preserve the beauty hence the fears of society are roused that a narcissus state might prevail in society in which the whole society is obsessed with a narcissistic idea of beauty that God is a narcissus having a schizophrenic disorder and as such the God possesses an alter ego of a narcissistic disorder and thus the organized religion fails.
Just to preserve the status quo of organized religion the rebel is usually dubbed as without a cause for the religion is compelled to pass an aesthetic judgement on narcissistic tendencies which might be otherwise attributed to the God. The religion usually ignores rebel unless the rebellion is against religion which in this case makes the rebel having a worthy cause.
But rebel without a cause is laudable on the grounds it allows harmonious play of intellect and imagination.