Tieflings have been around for centuries, and are intelligent and charismatic. They aren’t going to not make it into history books/stories, and we know from the phb that they aren’t all evil.
What are you talking about? D&D hasn't even been around for centuries...
I never said that they are "all evil", but if you would bother to actually read my post, look in the PHB, and read the description of Tieflings, you would understand exactly why I wrote what I did. Since you don't seem willing to do this, let me put it here.
"To be greeted with stares and whispers, to suffer violence and insult on the street, to see mistrust and fear in every eye: this is the lot of the tiefling." For further evidence, read the section on Mutual Mistrust. While the Tiefling's heritage doesn't mean it must be evil (one of the Tieflings in my game is Chaotic Good, actually...), I simply warned my players about the reaction they are likely to get, which comes directly from the PHB. Dragonborn follow a similar bend.
We dont need Forgotten Realms novel characters to have a sensible history.
Well, then, what "history" are you pulling from? As I said, those are the only two I have read about so far. I am sure there are other novels, fanwork, etc. about Tieflings, but unless you have a source for your history you have nothing to base it on.
You can make any assumptions you want, but nothing about any dnd 5e phb race necessitated them being shunned or mistreated in every town the go to.
Sure. Nothing necessitates it since every DM can run the game as he or she wants, but the
evidence quoted from the PHB supports initial reactions of shunning and mistrust.
At any rate, if you choose to ignore the text in the PHB, that is your choice. But this thread is about half-races, so I am not going to debate the issue with you further as this is not the place for it. Have a nice day.