To add a anti spam advanced setup i need to give the rule name (exact), and drop or create the rule. It would be better to have a + icon, get the whole list of rules, select and then give custom score and add it to this list.
Second point is that if we want to change the custom score, we need to remove the rule and recreated instead of make this changable.
This is an advanced page, and requires an advanced user to know the rule names. The rules already in the list can be managed through an advanced page, click on "Click for more details" to know how.
The whole set of rules and default scores is a long list and there is not a unique score for most of them. Then, keeping the list up to date can be a hard task.
This is an advanced settings page. If a user knows what a rule means, we prefer let them write the rule name rather than choosing from a very long list