I think you're confused. iShank is an admin, not a donor. A donation doesn't give you any powers, just some plugin immunities, a reserved slot and a couple other things.
And like cirno said, we allow some swearing as long as it doesn't become distasteful.
Again, the reason you were banned as such is because you disrespected an admin, knowing he was an admin. If you had not known he was an admin, you would simply be disrespecting another player, and you would probably just have received a warning, if it was even warranted.
As for the mutes, those are only effective for the current map and they're generally given out to anyone micspamming or being abusive on mic.
Finally, if any of the admins were acting inappropriately, please let me know in a PM and I will deal with it.
Edit: Thread locked