Only the person who created this group or someone they designate, can remove a member.
You can remove yourself from the group.
You can change how you receive emails, to a daily digest or no emails.
Without emails you can check the group conversations using a browser. The address is shown near bottom of every group email.
This group is not very active with very few posts except for spam, you might just unsubscribe or choose " no emails", you can still get notifications of responses to a conversation you post.