Site slower to load

I’ve got this plugin running on 35 sites, and overall I’m quite happy with the vast slow down in spam form submissions (even recaptcha wasn’t working). But I’ve noticed that page speed has taken a hit. I don’t have forms or even commenting on 90% of the pages on any given site. I see there is the option to exclude URLs; the thought of having to manually set that for so many sites seems daunting.

Am I missing something obvious?