In a game like this, votekicking being implemented as any sort of solution to problem players is really decade-old logic. There are better ways to achieve the result you’re looking for without putting that power into the hands of characteristically irrational players who, more often than not, just manage to ruin matches more than anything else.
Team damage happens to the best of us. Granted some LMB spamming Vangaurds, and the like, are much more prone to causing it. But even among those of us who do make an active and mindful effort to avoid it, it can still happen from time to time. Sometimes it even results in an accidental death. Other times, for many, it is not so much accidental as it is player negligence; or even purposeful.
Calculate the team damage, either as a whole, or from life-to-life, and adjust respawn timers accordingly. The more team damage caused, the longer the respawn wait. If the team damage was accidental, and minimal, the respawn timer won’t be very long, and the player will likely try to avoid it. If the team damage was purposeful, or based on negligence, the player is less likely to stay in the match and wait their extended duration, or they are more likely to avoid future team damage due to the extended respawn penalty. Hitting multiple team members will cause large amounts of team damage, likewise hitting a single team member to death will also cause large amounts of team damage.