This headline isn't accurate and the source is incorrect here--my group was just there in Overath very recently on a joint German-French mission team-up and the actual reason is much more prosaic, ie. just that Overath is right next door to Cologne that has a very large Weihnachtsmarkt (Christmas market), one of the largest in Europe in fact, and it's redundant and costly to have a separate one in Overath when most residents of the city head to Cologne next door anyway. That's it, and really isn't anything new, it's a case by case and year by year decision for the smaller or medium sized towns, and in some cases here Overath has had its own festival while in other cases mostly deferring to Cologne or other neighboring cities, without doing a formal one of its own (although smaller decentralized markets still take place). And inflation and cost increases have been a general issue causing Christmas market adjustments and cancellations, including in the U.S.
We've been learning too of dozens of Christmas market cancellations all over the United States from our affiliate churches there mostly due to cost (and cost-of-living) and affordability challenges too. Yes, security does figure into such cost calculations--that's always a cost consideration for any festival, as law enforcement and private security need to be contracted (we're quite literally tackling this now for one of our own upcoming events. And we among other groups have been heavily involved (and lately seen historic success) in welcoming former Muslims into the church, who often come to us in fact as part of the process of embracing their new countries and their centuries of history, with roots in the church and the word of the Lord in the heart and soul of the society itself. On this particular point nevertheless, this really isn't the issue at all. Large open markets are always quite expensive to run, and not just due to security costs, and with Overath so close to Köln, it often makes little sense to hold a separate event, in this and in many previous years it just makes more sense to merge and hold the main event in Cologne.