I think alot of them are either new, trying stuff out, or bored, or thinking they are helping, or they tried to get a goon in twice and the fighters werent keeping the enemy down, so they took the matter in their own hands.
This is like the 20th thread in the past two weeks on the matter. The fact is, no matter how much people complain, or try to teach people to take the town first and the hangers as a last resort, there will always be Mike4673 that will come into the game and just go bomb stuff.
The best thing to do is accept that this is the design of the game at the moment, and hopefully future changes will allow fights to continue during base capture attempts.