Context (and caveat): I'm posting this on behalf of a friend.

A friend and fellow player in my D&D group recently approached the rest of our group for advice on a number of issues she was having with the home game she was DMing. We pinned down and worked out the major underlying issues just fine, but a side issue caught my curiosity.

The setting she was running is a lightly-homebrewed Forgotten Realms setting, and one where necromancy was viewed very negatively, to the point of being considered outright evil. One player was dead set on playing a necromantic sorcerer. This character had a lot of fit issues with the setting, and my friend informed him many times that his choice, lore-wise, would mean his character would face a lot of hatred and hardship from the world, as necromancy was considered evil. His response was thus:

Also, as you said, it's your campaign. You run how the world works, any obstacles that come about are the ones you want. I didn't make an evil character so if you wanted you can easily make it so obstacles don't come about.

(The arguments are also tied up in a couple other issues that are only related in that they are red flags for a problem player; I can add more context upon request.)

Now, our group is very RP-centric, with a high ratio of "actor" players (or a tendency toward Watsonian perspectives, if you're familiar with the Wastonian vs. Doylist paradigm), and so our immediate reaction was that this was terrible entitlement, the sign of an amazingly self-centered player, and she should never game with this guy again--which she's a bit nervous about, as he was a friend before he was her player.

Ultimately, the most central issue--which is something different--is being worked on first, so this problem isn't likely to be immediately addressed. I'm interested if others have had problems like this before.

Have you ever had a player ask you to ignore, change, or otherwise "handwave" the lore of your setting in order to enable their character concept to be played without RP drawbacks or consequences? How did you deal with it?

Answers drawing from experience are requested, and methods used to resolve issues like this that didn't end in "remove player from group" are of particular curiosity, regardless of whether or not they can be applied to this guy in particular.