I suspected: Cat bias on iNat?
However, I didn’t realize there were so many brave pet owners who dared to dress their cats. I assume they’re all wearing raptor handling gloves, are mortally wounded, or have the rare photogenic cat that doesn’t mind the costuming (e.g ragdoll).
In all seriousness, I think part of it is new users who aren’t sure about what iNat is for and seasoned users who aren’t as rigid about the scientific purity of iNat data. Sometimes they are simply amazing observations like #18418933 (not mine).