I've nothing against Spain or immigrants playing for teams they want etc. But FIFA rules are weird and unfair and too many international careers are wasted because of it. For me I would prefer if a player can change NT if he played less than 10 games until the age of 23
Munir & Bojan never really deserved the NT calls but Spain wanted to ensure they won't play for someone else. Don't blame Spain for protecting its interests but I hope players will be aware of it.
Although at the end, if a player really feel that he belongs to one specific country, he should forget about football reasons
His father is clearly Spanish. The surname is at least. I can see that Transfermarkt shows that he has Spanish citizenship as well. So he is not an immigrant just because he was born abroad or has one parent (in this case mother) that is not Spanish. The case of many, many people, me included. In every country actually and such cases (mixtures) is only growing worldwide. Look at El Shaarawy for instance. Could have played for both Italy and Egypt and nobody would blink an eye or call him out.
Munir did a mistake early on thinking that he is bound to play a role for the NT team in the future. Since he never lived up to the initial hype and was not good enough his NT career "ended". Similarly with Bojan. But both of them were eligible to play for Spain. Both were half Spanish and both born in Spain. It is only their own fault and that of their agent and entourages. It must be a tough decision too as you are always confident at this level and especially if a highly rated youngster like both of them were.
BTW look at the current French team. 1/3 of them (if not 1/2) have zero French blood in them. If not more. Some of them were not even born in France like the likes of Umtiti. Yet few are questioning them. With good reason.
So players like Konrad de la Fuente, Bojan and Munir (with not only Spanish blood but being born there or having citizenship by birth) should not really be questioned. More their choices if anything which usually is only known a few years in advance.
I have much less tolerance for the likes of Qatar importing young Sudanese, Nigerians, Europeans, other Gulf Arabs and Arabs and neutralizing them in order to make them play for their national teams in handball, football, athletics and others. Here I much more respect the likes of KSA who although richer than all Gulf countries combined, are not doing such a pathetic thing.