>>37477822GF practically abandoned the dimorphism gimmick after gen4, only bothering for things like Frillish or the lion mons from that point on.
Which means there aren't that many, and Butterfree's is probably one of the easiest people tend to remember because it's actually a distinct mark that stands out rather than some subtle part of the design being a bit longer like in a lot of cases.
If you're that surprised from long term fans noticing Butterfree's obvious and well known difference you're just a retarded casual who probably came here recently with GF going into full kanto pandering.
