Bans are not at intended to "notify" the banned user.
They're not to impress them, or make them feel bad. They're mostly there to protect the rest of the users.
It's super cool that you prefer the "drive-by" style of trolling. And it's also fine if you crave the validation of a ban so much that you are unhappy if miss it.
Bans are not a reward for successful trolling and the lack of notification is a feature in this respect. ¹
Don't forget there are also the high-intensity trolls that derail a chat room and generally make it unusable for a prolonged period of time.
That's aptly prevented by small, time-limited bans.
¹ inb4 Request for badges on repeated bans