The same principle applies to the Swiss motorway tax: The residents who use the roads
And therein lies the problem - the Swiss motorway tax is a flat usage tax (one may think that it is a tad steep @40CHF... however going to Cannes one way on French motorways is going to cost you more than that)
Whereas you could argue that usage of Italian airspace and airport infrastructure is (or should) already be covered by ATC and landing fees and this new tax is nothing else than a wealth tax as opposed to an usage fee.