Yes, access to public places should be guaranteed for all citizens until it's proven they have ill intent, or until they wreck the place.
How would people feel if the guards stood at the end of Grafton St. and prevented access to certain people for no reason?... would this be tolerated by anyone? So the alternative is to allow unrestricted access to all public places (including public houses).. but that doesn't seem to be the case.
There should be exceptions.. but not 'sorry, regulars only'.. that's not a public place so. And defintely not every fourth person refused.. that's discrimination on the basis of meaningless labels applied arbitrarily to people, and not based on any facts about the person.