Ok. Hitting a shield has no effect on your moves. Same for attacks that do not connect at all. In order for your moves to refresh, your attack has to connect. When your attack connects, the move you connected with diminishes while every other attack in your moveset replinishes. Therefore, by spamming arrows, you are refreshing every other attack in your moveset, increasing the damage and knockback, while diminishing the damage your arrows do.
Example: I continually punish with fsmash for most of your stock. Now my fsmash is diminished. To refresh it in order to kill, I spam arrows. After 10 arrows connect, my fsmash is fully refreshed, so you die the next time I hit you with it.
I'm hoping that cleared up anyone's confusion about the way move decay works aka diminishing/replinishing, refreshing, or w/e else you wanna call it.
As for being cheap, just play to win. Even if your opponent thinks you're cheap, you still won the match and you were the one to move on to the next round, not them. So they can suck a **** for thinking you're cheap. It's their fault for losing to it.