It's a chat client. It's an addictive medium. It sounds to me like you're shooting the messenger.
Skype, Hangouts, or any IM client wants your attention. Slack is just a better version of all the other IM clients I've used (for work).
If you don't want to be disturbed you close Slack.
I suspect that if you've got problems with Slack, it means that there's a problem in the culture of where you work.
Where I work, individual @ mentions are barely used, maybe 0-5 per day. But there's nothing that's written in stone, or ever been discussed, it's just that colleagues respect each other's focus. Then the rest is less important that all can be ignored unless you're not concentrating on something.
