People aren't against the same-turn jump-in-jump-out because it's powerful in any way. Hell, for that price, you could get a Whirlwind that is almost as untouchable, but does much more damage. They're against it because it removes the interactivity from the game, something which alwasy strikes people as not being right. However, since most people don't understand that it's the lack of interactivity bothering them, assume that the squad is bothering them because it's unfair, the closest thing most people come to defining the real problem. But, since it is unfair, it must be unfairfor a reason, it must do something that is too good. Since this squad only does one thing, drops a template, that template must then be unfair. As a result, they blame the template for being far too powerful, when in fact it is simply irritating.
In conclusion: Hawks are uninteractive, not unfair. Except maybe against Guard.
The way I see it is they can jump in and out, and that seems very clear. Similarly, one grenade only seems clear.