I suppose there is something to be said for simple modifications, though bikes are relatively simple overall. I'm hesitant against making them difficult to work on as I wouldn't want to see a future when you must visit a repair shop to change a tire or something like that.

I had a read of the article you linked in another comment claiming '80% of e-bikes are illegal'. After a touch of searching around, I saw some numbers showing roughly a quarter million e-bikes have been sold annually in Italy over the last few years. Over the two days of that operation, the sample size was only 71 e-bikes. That's not particularly representative - though it does make a flashy headline.

Something I keep in mind when I encounter aggressive drivers on the road is that they are one of a thousand other cars I've driven by that day. Negative experiences tend to be more noticeable than the nominal sort. Besides that, it occurs to me if the authorities in Milan believed this to be as widespread as it may seem to the average pedestrian, they would do this regularly as it seems it would bring in €200,000 a day.

For what it's worth, I do like that they immediately confiscated those e-bikes. Between that and the €7,000 fine, sounds a good penalty to keep people from doing it again.