No, they shouldn't be disqualified, but neither should they be preferred.
We come back to this question. One of your colleagues asked me earlier whether I am opposed to politicians being appointed judges. The answer is absolutely not. What I am opposed to is giving preferred treatment to a candidate on the grounds that he's a politician, perhaps a retired politician or former cabinet minister, because his cabinet colleagues feel that he deserves some kind of recognition for his years of service to the party or the government.
I'm sure you appreciate that the reason I inserted the table—remember, it's only a table drawn from someone else's paper—is to indicate the correlation between political contribution to the party and the party that made the appointments.