I could see that you have set “Block Threshold” value to 2. We recommend to set it to minimum 20, as 2 is too small and most of the valid requests might reach that value. And that’s why the bing visitors are also banned.
The aim of HMWP IDS is to block malicious requests It detects Cross-site scripting (XSS), SQL injection, header injection, Directory traversal, Remote File Execution, Local File Inclusion, Denial of Service (DoS).
HMWP IDS detects malicious requests coming to your site and notify you about it. But all these requests might not be harmful and you need not worry as HMWP IDS will take care of this and will block the malicious requests if Impact level is more than 20 (default value specified in HMWP IDS). You can stop receiving emails regarding this by setting “Notification Threshold” option to 0 in IDS Firewall tab.
In above case, as the Total Impact is only 5, the request is not blocked.