Yeah, Holonomic's are never auite good at defense. However, with a good driver and some nice programming, you can avoid being pushed by dodging.

From a more technical perspective, It's actually quite clear why Holonomic's get pushed easily. Most of the time their rollers are made out of plastic, which when smooth isn't the best traction surface. Therefore a more gripping surface, like wedgetop, will have better traction.