The problem with this is that English has commonly been adopting words from foreign languages and retaining an approximation of their original pronuciation along with the original spelling, which doesn't correspond to original English orthographic rules, for quite some time.
If it is not "legitimate" to use a spelling such as Qameron in English, then it is not "legitimate" to use Gaelic spellings such as Niamh or Sean when pronouncing those names as "Neeve" and "Shawn", since those spellings do not correspond with normal English orthography. But no one ever tells an American parent who names a child Sean that they have used a spelling which is not "legitimate".
There are now enough uses of Arabic names like Al Qaeda in English speaking newspapers, along with trade names like Qiana, that use a "q" without a "u" that this orthographic form should be familiar to most literate English speakers.
I would agree that a spelling which makes a name almost impossible to pronounce, such as using writing a name "Mara" and asking people to pronounce it like "Sarah", would not be orthographically "legitimate". But it seems to be that a spelling like Qameron, where it would be clear to the great majority of literate English speakers that it would be pronounced the same as Cameron, should not be called "illegitimate" just because it doesn't follow a rather arbitrary orthographic rule.
This also doesn't seem to recognize that names just don't have standard spellings the way dictionary words have. I really can't imagine Harvard, or even Oxford or Cambridge, refusing to use a spelling like Qameron or Ka'yasia in official records if that was the legal name of the person being referred to. Editors don't "correct" spellings of names the way they would correct spellings of dictionary words. They would be wrong to do so.