Spamming weapons is where you build about 999999999999 of them, and use only that. Particularly when the unit isn't meant to be used in such numbers, but just in small amounts to bolster your existing forces. Usually, even with such a focused army with no variety, you still have about a 99% chance of winning. ie, if I were to build thors hammer tigers and nothing else, and you have a good mixture of ESG, Supernova, RPG etc, u would still have a chance to win, but not a very good one, unless you used some crazyass strategy, and even then itd be tricky. Spamming weapons detracts from the game a LOT imo.