Besides, when the Sanji vs Luffy stuff happened, at the time Sanji was just thinking he would be forced to marry Pudding and that's it.
At that time, Pudding was the beacon of hope for Sanji in all that mess.
Once he learned the truth about her and that he and his family would be assassinated during the wedding, shit just collapsed.
His first instinct is go back to Luffy.
Again, wth is wrong with all of this?
I understand being annoyed at a Robin 2.0 situation, but just because these are similar, doesn't mean one is good while the other is bad.
Besides, Robin was chased as cast away due to being something she wasn't, which was some "demon that shouldn't have been born".
While Sanji was cast away by his family due to being EXACTLY what he was. A kind and normal kid. They are fundamentally different situations.