I'm not sure by exactly what criteria enthusiasts should be judged. As Marlon says, there are a number of late middle aged types who don't really give a stuff about pedigree or performance. However, I thnk the same number who haven't had Alfas before seem to like how spirited the cars are, and also often comment on the lively performance.
I do agree though, the 1.6 engines are a bit pedestrian. ~Then again, as my first Alfa was a 1.6 Giulietta, then was I not an enthusiast? Was the induction sound, the rasp, the cammy growl and performance which saw off most 2 litre cars, and XR3s all lost on me? Was I unimpressed by the technical specificatoin and the advanced layout (then) of the car? I don't think so.
There is no black and white regarding this. I would like to say that some time ago, I think the was published by the ABD, that the Alfa GTV and 147 were the cars most likely to be flashed by speed cameras.
I think that there is two distinct types of Alfa owner. The first perhaps buys the car for the stylish looks, but has considered many other cars also. The second is more likely to be a hard core Alfa fan. One who has had pervious Alfas, and how is attracted to the blend of performance and spirit, but who also likes the style and image afforded by Alfas. This, coupled with high insurance groups and repair costs may help explain why a larger percentage of these cars are subject to insurance claims.
Also, I think that these figures are perhaps expressed as a percentage of ownership, and not absolute numbers. I'm sure there are more Vauxhall Astras involved in an insurance claim in one year than there are Alfas in the country.