The first ban for spam is a 1 day ban already. It then progresses to 5 days, 2 weeks, then doubles per offense. A mute/gag + warning, followed by an rmute/that is applied per session before the ban. So nobody is getting banned for spam unless they're doing it 3+ times per session and repeatedly ignoring warnings, and nobody is getting banned more than one day unless they're managing to get banned more than once in a short period of time.
A 5 day ban for mic spam second might seem harsh, but at minimum you would have needed to spam 6+ times over 2+ sessions, ignoring 4+ warnings, and having already served out a 1 day ban for a previous offense.