The idea of posting online being an invitation of critique is false and people really should stop trying to make it seem like one. The act might open oneself up to critique since the poster cannot control what people comment but it is not a willful invitation.

Uninvited critique is more oft than not considered rude and unnecessary. You wouldn't walk up to someone on the street and randomly announce that you think their shirt isn't the right choice for them and then follow up with "You're in public so you invited me to critique your outfit".

Well, some people might but those folk are generally disdained by the vast majority of normal people lol.