It might be a preemptive move if they saw an 'uncomfortable' level of OMG interest in local legitimate bike groups/events. The US ATF reported several years ago the OMGs were targeting vets. There might have been some more recent and local intel.
With some legitimate veteran biker groups apparently wanting to mimic the appearance of OMGs, I can see how OMG intermingling and infiltration can happen. It's apparently 'all about freedom', but I don't get it. I've been riding for 50 years and never had the urge to look like either a pirate or OMG.
I can see the concern. A Legion branch was recently 'de-chartered' because of OMG infiltration.