One of the most severe problems of a democracy would be having a leader that is not qualified to lead anyone. As an objective news article notes, Obama fits this quite well. There are two ways to read his actions at this event. The first way is that Obama genuinely believes that La Raza is good for the country. The second way is that he does not believe this. If the first way is true, then Obama is a fool, but if the second way is true then Obama is immoral. In either case, Obama is not qualified for office.
If Obama believes that La Raza is good for the US, then he is a fool. La Raza is a group focusing on race. It is no different than a white supremacist group except that it is Mexican. They also support a group that wishes to conquer the American southwest and return it to Mexico. A wise person would not support a group that undermines the security of the US. Since Obama is not merely a citizen of the US, but a president, he is under a greater obligation. Therefore, he has to do more than deny support to a group that attacks the US. He must seek to marginalize such groups and use every legal method to make sure that they no longer exist. Since he is supporting them, if we assume that he believes they are good for the US, then he is not wise enough to know these things. He is foolish.
If Obama believes that La Raza is not good for the US, then he is immoral. Knowing exactly what they intend to do, he supports their activities. He is actively attacking the US. For a president who is under obligation to protect the people of the US and the US, this activity is extremely immoral.
Since there are only two options, Obama is either immoral or foolish. Since the consequences of either action are severe, Obama is not qualified for public office. Supporting a group that wishes to separate from the US, and is willing to consider force to do so is not something that a president can do. If he is too foolish to realize that this is what he is doing, then he is too foolish to hold public office. If he is doing this and knows the consequences then he is far too immoral for public office.
This illustrates a key fact of any leadership qualification in any form of government. A leader must be wise and moral. They must be moral so that they will not be partial to one part of society over another (such as the racist La Raza). They must not take bribes or be intimidated by others. They must be wise so that their decisions will actually benefit the common good. If they are unsure of an action then will consult someone who is likely to know the answer. It is these traits that we are supposed to check for in someone before we elect them to public office. Since Obama was elected on a racial basis and on a rhetorical basis (he gave good speeches), it is not surprising that he is unqualified.