>> Who studies philosophy in school when graduates becomes a historian of philosophy, not a philosopher.
> No, when they graduate, they become a degree holder in philosophy.
No, what they become is a historian of philosophy. Because what they learn is the eminent philosophers and schools from the past, and the philosophical methodology. This is like studying hittitology, they get to learn the hittite language, the hittitle literature, and they practice their writing on actual stone tablets, but at the end they become hittitologist, not hittites. What the education system in a given country considers a graduate from a philosophy course of a university is irrelevant, that's just a bureaucratic title.
>> Requirement of a diploma to philosophise contradicts philosophy itself.
> Similarly, formal education in philosophy can be useful to those wishing to do philosophy well.
My words agrees yours. I don't say a diploma is futile, just that it's not a requirement, and it cannot be one. Nor do I say that it's useless.
>> Philosophy is not a job, it's a personal trait [...]
> No, its not. "Philosophy" has at least two related senses, one of which is a thing one does (perhaps as a job, perhaps not), and the other of which is an a label for a class of belief systems, [...]
>> Philosophy is love of wisdom.
>The English word "philosophy" derives from Greek for the love of wisdom, but that's not what it means. Etymology is distinct from definition.
A personal trait is a group of things one does anyways. If one is timid, he does things that makes him timid. Philosophy is such, it includes thinking, doubting, searching, discussing and deciding.
You are mostly describing a western, originally-catholic, formal and academic sense of philosophy. I do not stay within that confining context, and think that the first and foremost task of a philosopher --and a task that continually shows up in whose life-- is to define what philosophy is, a task unachievable if one just opens some dictionary's P section and accepts whatever he finds there.