Italy knows plenty well about internal terrorism. They had the years of rage in the 1970's and 80's with kidnappings, bombings, etc. from the various Communist and Fascist terrorist groups.
Different kinds of terrorism, to be fair.
One could argue the communist and fascist terror groups had "common principles" with the general population, or shared some to some very broad extents. Just like all, or most, of the political or independence movements they have a fairly defined target: a system, a government, its institutions, its representatives, etc...
Whereas the "imported"/"repatriated"/"refugee welcomed"/etc... ones don't make these distinctions. Their targets are all around them; like a pit-bull left unattended in a park full of toddlers.
They won't attack institutions, their representatives (or very rarely), governments, are things like that. Instead they will simply go after absolutely random people, at absolutely random places and absolutely random circumstances. It can be in a train, in a restaurant, outside a school, in a busy street, at some festival, in a building hall, in a parking lot, etc...
France also had experience with internal terrorism, banditism and such prior to Islamic terrorism and serial stabbers stealing the spot-light. And yet, not only were we not safe, but we also got taken by surprise.
"Anyway, I just started stabbing"
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