it seems like an easy way to save time and money on hiring
If you are seeing this change based on whether you exclude people without comp sci degrees, what you're really seeing is your recruitment firm/ team's lack of effort or expertise. It's literally the job of recruiters to separate the wheat from the chaff. If you're doing it yourselves by putting hard restrictions on the recruitment team to remove the bad results they are letting go through, you should be taking a hard look at that company or team.