Yes, yes you are missing something.

It's like asking why people liked Robocop when it's a copy of the British Judge Dredd.

Or the people that liked Star Trek 5.

I've enjoyed the Starship Troopers novel (I read it first back in... 1982 I believe...) and the animated Roughnecks, and I enjoyed the feature film as well.
Okay, I didn't really care for SST2, but most people didn't. The film has slick visuals, decent acting, a good ensemble cast and nice costuming. Everyone harps on and on and on about there not being the powered suits. Okay, that was a little disappointing, but after 15 minutes of watching the film... I got over it. Seriously, George Lucas had a bouncing gold-medal winning digital Yoda and I hear less complaints about that than I did about the lack of powered armor in SST.

Maybe I'm in the minority. I still like the film to this day, I saw it in first run in the theater. I've owned copies on VHS, VHS Widescreen, DVD and finally the special 2 disc DVD edition. I'll probably end up buying it on whichever High Def format survives the war.
It has action. It has romance. It has good characters... and guns... lots of guns.

What more could one want?
There's rumors that in the Third film we may finally see the "ape" armor. Since Ed Neumier is writing the screenplay, and since digital FX technology has come a long way in the last 10 years, anything is possible.
Wow, I just realized I was ranting. I'll go shut up now.

Russ