From a legal standpoint you’d want your candidate to be able to serve if elected.
But an ethnic minority party that gets around 10% of the vote is no threat to come close to winning so what does it matter. Several minor US parties have run candidates for Pres/VP that weren’t eligible.
This candidate has not broken any law except he ran against the dictator and got over 10% of the vote. And he is friendly to Kurds. It is common in Turkey to build a coalition government because normally no one wins the majority directly.
Now, with Erdogan the Islamist as the dictator with his emergency powers he can arrest whoever he likes and if he does not like how the court rules, he overturns the judgment and fires the Judge.
How is that for a system?