用户未允许聊天时，用户卡片上的聊天按钮

[Firepup650 (Firepup Sixfifty)]

That’s indeed right, this post by robot (his only in that topic) doesn’t have the chat option:

Full Screen Login & Create Account - Feedback

this would also run afoul to their guidelines for social logins, we’ve had a few sites notified about non-compliant facebook buttons in the past (social login requirements might also be why some say “log in” vs “sign in” though I’m not 100% on that)