I am quite puzzled there - since the FW190 were in different types.
I may assume the FW190 - without the letter - bundles the whole of A, G and F types (forfeitting numbers atm, since an A2 is quite different from an A8)
I also understand that in a full ETO game things may look different, and that as the war move on and on, the Luftwaffe was more worried to protect the skies of Germany than to have large presence upfront. (I shall briefly mention that ontop of that I am quite a sucker for 'possibilities', like if Germany had the production points / resources, they may have churned out earlier Fw190D or produced more quality planes, etc - but that's for another topic).
So I can see that the 'red bolt' is probably a mixing up of the FW190 G and F (suited for ground attack as fighter-bomber proper) with the bulk of FW190A - I am still puzzled at the vulnerability - and I'd have split the FW190 in more units (the FW190A could have got the white bolt at best or simply limited to strafing) and have only 1 red bolt type.
But why the vulnerability? It was quite a sturdy plane.
Although we use the terms "vulnerable" and "tough," the thing to remember is that they are really just modifiers to strengths which allow us to rate units at half steps between the whole number combat values. Think of them as sharps and flats in music. In the case of aircraft, a 4 Vulnerable means the aircraft has an attack value of 4 but a defense value of three. The word vulnerable is what's causing you the problem, but don't worry about the word. We could as easily have made the numeric value the plane's defense rating and had the modifiers increase or decrease its attack. In that case we would have called the Fw-190A a "3 Deadly," and I bet that wouldn't have raised a flag in your mind. Sure, an Fw-190A was deadly. But really a "3 Deadly" and a "4 Vulnerable," although they sound different, are exactly the same in the game: a plane with an attack value of 4 and a defense value of 3.