The left-right political paradigm is originally based upon the parliamentary division in post-revolutionary France. On the right sat those who advocated the maintenance of a hierarchical society controlled by aristocracy. On the left sat those who advocated the post-revolutionary values of religious and political equality and freedom. In the centuries since these ideals have been disputed and appropriated, including in their theoretical manifestations from liberalism, to Marxism, to modern conservatism that paradoxically applies them to justifying the defence of an established social order.
Charlie Hebdo adheres to these revolutionary values: it believes in religious freedom, but opposes the suppressive influence of any religious sect, which includes the right for any philosophy to be subjected to criticism and ridicule whether academic or satirical. Charlie Hebdo has consistently opposed discrimination and bigotry against ethnic minorities in France. Getting straight to one point of contention: some of its caricatures have been criticised as racist. Even though this implied racism or xenophobia would inconsistent with the morality Charlie has advocated for the entirety of its history, it is still a justifiable criticism to question the taste and motivation of those particular cartoons. This is the point, we have the right to do so constructively if we are to live in a democratic society.
Conversely, it would be completely illogical to consider that the murderers were motivated by this controversy. Nor were they likely solely motivated by an illustrated portrayal of Muhammad; offensive to Muslims, yes, but the overwhelming majority of whom who adhere to stringent standards of morality, peacefulness and tolerance viewing such an assault on humanity as the most abominable act imaginable. The cartoons were an excuse at most for ruthlessly assaulting Charlie's opposition to fundamentalist Islamism, and the mischevous attitude accompanying it that challenged the self-righteous and oppressive piousness that all fundamentalists and totalitarians rely upon to assert themselves.
The likes of ISIL and al-Qaeda, which the murderers pledged allegiance to, are virulently racist with an established history of ethnoreligious persecution and cleansing. The West appears to have forgotten ISIL's attempted extermination of the Yazidi and Kurdish populations within their captured territories. Antisemitism is also an integral part of their ideologies; historically this is the basis of why fundamentalist forms of Islam were compatible with Nazism. Even though Hitler viewed Arabs are racially inferior, and despite the supposed secularism of Bath'ist leaders aligned to the Axis, Hitler admired muftis who shared the cause of Jewish persecution and eventual elimination. This common holy war recruited Muslims from Yugoslavia into the S.S.
Concurrently, the Vichy puppet regime in France replaced the motto "Liberté, égalité, fraternité" to "Travail, famille, patrie" in an effort to erase the humanistic post-revolutionary values from the national consciousness. The religious motivation in this case was a fundamentalist form of Roman Catholicism, but the repression of human rights facilitated and justified by it was the same as that adhered to by Nazi-aligned Islamic extremism. More commonly in the modern day, Islamic extremism and the far-right are mutually symbiotic cancers, with the former relying upon the encouragement of racism, hatred and discrimination to recruit and brainwash the disillusioned that the latter fundamentally relies upon for its bigoted and stereotyping propaganda narrative.
Those of us who believe in human rights and democracy, therefore, should fundamentally view such extremists as anti-humanist nihilists no matter the ideology or "faith" they project.