Fortunately, you can tell Gmail to really mute such threads — until a message in the conversation is address to you and only you. (Somebody specifically adding you as a To: or Cc: recipient will also bring the conversation to your attention.)
Mute Reply-All Threads Successfully in Gmail
To have Gmail hide new messages in muted threads unless they are address only to you or somebody specifically adds you to the conversation:
- Follow the Settings link in Gmail.
- Go to the Labs tab.
- Make sure Enable is selected for Smart mute.
- Click Save Changes.
- Mute all unwanted conversations.

