I don't think it makes you bad. However, if there is someone in the aisle that only wants one clonetrooper. You have 25 in your arms it might be nice to spare one of them for the poor person. You know what I mean? I mean you have 25. He has zilch. LOL!
To me, that's the main difference in army building that I don't think a lot of people take into consideration when they bash army builders, like rebeltrader mentioned he experiences.
A true army builder might be buying 25 of the AT-TE Gunner in the aisle, but would (I've found) happily hand you one if he/she were asked nicely.
Someone who isn't so scrupulous will look at you like you're insane when you ask him/her to part with one of those 25 AT-TE Gunners so you can finally have it in your collection. After all, that little guy is going to pay for his/her retirement, don't you know.
To put army builders and army hoarders in the same boat is, to me, wrong and insulting. Army builders are opening these figures to make dioramas, or photo novels, or what have you; army hoarders are locking them away from light and the elements so they can have them AFA graded and sell them for 100 bucks on Ebay.
So, to all you army builders, don't feel guilty because you're doing it for the right reasons. Just don't forget to give your old pal DoctorPadawan one of those 25 Clones since he's on your side and all.