It's not just any post. This was a birthday message for Slash, on his 56th birthday.
From what I know, Joe Perry's son Aaron manages all social media accounts for Joe Perry, Aerosmith & Hollywood Vampires. This looks like a copy-paste gone wrong.
Aaron's a cool guy, but someone did screw this up 
It's not all bad. Check out Aaron Perry's interview on The Simp Life podcast here.
LE: same mistake on Instagram. Or is it?