Really? I've not personally witnessed any bullying behavior in the flocks that have appeared in my yard(s) over time. They are beautiful to watch taking off together.
What I don't like seeing are the grackles. And the worst offender ever was a single mockingbird, in Georgia, who literally staked out my yard as his personal territory. He'd sit in one of my trees and go after anyone - including these blackbirds - who dared swoop in to a feeder. I'd watch him run everyone clear out of my yard and back to the treeline, then he'd return to his station in the tree. He was a little jerk!