After the demise of FEAF and then NEAF, fast jets rarely went east of Cyprus for over 20 years. Between 1970 and the mid 90s the only rare excursions to areas of severe thunderstorms was the occasional FI rotation. Consequently, there is a generation, or two, who have not grownup to respect thunderstorms.
Since the advent of radar it is difficult to believe that some fast jets have not had one fitted. Obviously ,all “Fighter” ac since the Lightning have had a radar and so have been able to weather avoid. I do recall, however, flying through atrocious weather over the Alps with the lead Tanker “pressing on regardless”.
It was only in the mid 80s in Europe that it became more acceptable to ATC to request heading change to avoid weather. In the USA Air Traffic had a far more flexible approach and re-routing to avoid weather was accepted.
With modern radars it takes a conscious thought to select Pulse mode; otherwise the cells are invisible. That thought process must start in training. Too often I observed experienced Instructors who failed to select the appropriate radar mode when flying near severe weather.
I also recall some dreadfully nights in the mid 90s trying to AAR over the Adriatic in thunderstorms. Some of the Tanker Captains seemed to think that staying on the Towline was the most important thing. Trying to tank off a 135 with a BDA near/in thunderstorms was not my idea of fun!