Obama has actually made a point of appointing people from a wide range of genders, races, ages, and sexual orientations. Any excess amount of white males is most likely due to the excessive number of white men in politics in general. Even if Obama tried his hardest to appoint an extremely diverse population, it would be difficult pulling from the pool of possibly candidates.
I do not think that it matters what race or gender the people are that Obama is appointing into office as long as they are capable of doing the job for which they are appointed. If Obama were appointing these people based primarily on race or gender, then yes, that would be a problem.
Obama is not appointing too many white males. For one, the notion that there can be too many white males is a view of racism. 60% of the country is white and males at this moment make up the majority of politicians in this country. I believe he's appointing the most qualified people for the job.
Think about it, if you have a certain amount of people where 70% of them are white guys. Then you randomly select 50% from that same group of people, you will end up with more white males that any other demographic In the US there are more white men in politics than any other demographic, therefore President Obama is going to appoint more white males than any other demographic.