Yes, the article is correct in the way, that number of guns among population is increasing. However, there immigration is only partial story. The other part missing from the article is failed states experiencing increasingly ineffective apparatus unable to deal with almost any issue lets be economy to social security to safety. The number of guns in the Central-East Europe is increasing, and coincide with the weakening of the centralized state and public safety. Czech Republic has liberal gun laws as is it has USA. They already had mass shooting in February 2015 when retiree gunned down people in the restaurant. People are arming because they do not believe state will protect them. The number of illegal guns in Central Europe is incredible. While immigrants are generally adding oil to the fire, the trend started years earlier.
Another big unspoken fear is that present neo-communist multi-culti ultraliberal regime will crack down on civic liberties. This already caused weakening such institutions of democracy like freedom of press and speech. Germany which used to be top five most free press country slipped 14 below the Czech Republic. Press is getting censured. Discussion are blocked, and people get prosecuted by government by disagreeing with handling current migrant crisis. In region which experienced both left and right wing dictatorship, people are not ready to be put to slaughter in the name some of the social experiment. People on the left, right, and middle are arming for that specific reason.
Very simple review is how passive was public in the 90's in Central Europe and radicalization today, where you can see mass demonstration all the time. Couple years ago, a dude stolen tank in the armory in Hungary and drive to it in front of parliament buildings. In Slovenia, people burned the town halls during the riots. Similar riots against government institution happened in Latvia. East Germany experiences large violent demonstrations on weekly basis. Yesterday bunch of people were injured in Dresden. German press even does not bother to report the evens at all. Huge demonstrations happened in the Czech Republic since 2011. Once the flood gate will open, I am pretty sure Europe will experience civil war between masses and the establishment. Immigrant crisis will strain the economy which still operates bellow 20088 level. Even wealthier countries like Netherlands and Finland never recovered to the pre-crisis level.
Look for problems in the under performing economy and nothing will change that. Over the weekend, liberals were totally routed out in Poland. While Polish economy expanded by 25% since the crisis, current young Polish generation will experience significant reduction of the living standard. Bad economy, ineffective state apparatus is always receipt for disaster.