Hello,
There is actually criteria clarification on graffiti such as this, as well as murals and street art in general that may be helpful to you:
Besides the Review Support thread, there is also the Criteria Clarification Collection thread, and there are several different topics here that may help when reviewing.
Yes, there are Wayspots out there that no longer meet criteria, or never did, but may have gotten approved by the community. One of the issues I have in my city is people nominating Little Free Libraries (LFL) that are on single family private residential property, PRP for short. LFLs are eligible, but if it’s at an ineligible location, it shouldn’t be accepted. Luckily, I’ve been able to get these removed, and I’ve even had the homeowners thank me for doing so. With that said, you may want to look at seeing if you can remove some of these Wayspots, and more info can be found here: