Starship troopers. Why would they fight the bugs in that way?

Agreed. Why not use long range laser weapons ?? Certainly they could use high explosive bombs that could be guided in remotely.

Probably the same reason in Pacific Rim they faught giant monsters with giant robots instead of developing a germ or other form of weapon to combat the Aliens. I guess the simple reason being - it was more badass haha. Starship Troopers would've ended pretty quick if they just bombed the Bug planet.

@Chris Picard

Ah, that's true! Also it's the only reasonable way for many of the future folk to become citizens.