The EU is a funny place at the moment. Most politicians who seek prestige don't bother with the EU, they do national politics. Most national media does not cover EU material, but focuses on national issues. This leads people more focused on the bigger picture to seek out working at the higher level. On the other hand low performers are also sent to Brussels because "In Brussels no one can hear you scream".
Anti-EU sentiment is generally driven by national politicians who somehow always seem to cast blame on the EU when things go bad and take credit themselves when things go well. Even going so far as taking credit for implementing laws they were actually forced to implement by the union.