it's fine to compare, especially when you're talking about playing milsim lol
People always get the comparison wrong though. It's easy to say "oh I could shoot that guy if I had a real M4", just like if you lost a street race against a honda civic you could say "oh I could have beat that guy if I had an F1 car"
Well you don't currently have a real M4, or an F1 car.
And if you had an F1 car, and you were racing, it would only be against other F1 cars.
And if you had a real M4, chances are pretty high you'd be engaging people with other real firearms lol
So more realistically, if you had a real M4, and the guy you're trying to shoot had a real gun, and you were on open ground, chances are pretty good you'd start shooting a lot further away than 200 feet, like as soon as you could see the guy, like 500m? sound reasonable? Well then you'd have a hard time trying to hit that guy. But you'd be all like "man I could hit that guy if I had a sniper rifle"
Basically, just scale everything down to being reasonable.
Max range of an M4 is 500-600m, but you won't be trying to one-shot people at that range, wind and foliage are going to play with 5.56 out at 400m.
Max range of an airsoft gun is 240-300ft, but you complain about the same shit. The foliage and wind affect the round a bit more, but basically if you're engaging someone at 280ft with an airsoft gun, you have to compare it to shooting someone at 600m with an M4
It's still a game, but I find the comparison works great when you think about it rationally