It's all in a name. Historically, German people have had negative preconceptions about people with certain trendy Anglo-American names like Kevin, Mandy, and Peggy—so much that there's a Wikipedia page about "Kevinism."
According to a master's thesis authored at the University of Oldenburg in 2009, certain given names of students can indeed lead to prejudices on the part of teachers. For example, the name Kevin (an anglicised name of Irish origin), given to a German child, indicates to German teachers that such a student is prone to attention-seeking behaviour, as well as lower scholastic performance, and is also indicative of a lower socioeconomic status. It was not possible to determine whether this also causes a student to be treated less well. Prejudice of this type is understood to be more prevalent amongst teachers in Western Germany. English or otherwise exotic given names are often understood/stigmatised in the old states of Germany to be typical "Ossi". In fact, English given names in East Germany were particularly popular in the two decades preceding German reunification. There, this trend was also popular amongst the middle class, while the preference for such given names today, particularly in Western Germany, is perceived as a lower class phenomenon.
Some people consider these names to be markers of low social class. Though names do have correlations with parental income and education, making broad generalizations from names can be a slippery slope. In Germany, "Alpha-Kevin" was, for a time, at the top of the list for an online poll for word of the year in Germany, meant to describe a "particularly unintelligent young person." However, it was struck from the list because it was so mean.